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Association between maternal alcohol consumption during pregnancy and risk of preterm delivery: the Japan Environment and Children's Study

Association between maternal alcohol consumption during pregnancy and risk of preterm delivery:... DOI: 10.1111/1471-0528.15899 Epidemiology www.bjog.org Association between maternal alcohol consumption during pregnancy and risk of preterm delivery: the Japan Environment and Children’s Study a b c d a S Ikehara, T Kimura, A Kakigano, T Sato, H Iso, the Japan Environment Children’s Study Group a b Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, Suita-shi, Japan Department of Public Health, Hokkaido University Graduate School of Medicine, Sapporo, Japan Department of Obstetrics and Gynaecology, Osaka University Graduate School of Medicine, Suita-shi, Japan Osaka Maternal and Child Health Information Centre, Osaka Women’s and Children’s Hospital, Izumi, Japan Correspondence: S Ikehara, Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-shi, Osaka 565-0871, Japan. Email: s-ikehara@pbhel.med.osaka-u.ac.jp Accepted 22 July 2019. Published Online 25 August 2019. Objective To examine the association between maternal alcohol of preterm delivery. Heavy alcohol consumption (≥300 g ethanol/ consumption during pregnancy and the risk of preterm delivery. week) during the second and third trimesters was associated with a four-fold higher risk compared with non-drinkers (multivariable OR Design Prospective cohort study. 4.52; 95% CI 1.68–12.2). Light alcohol consumption (1–149 g Setting The Japan Environment and Children’s Study (JECS). ethanol/week) tended to be associated with lower risk of preterm delivery (multivariable OR 0.78; 95% CI 0.60–1.00). Population A total of 94 349 singleton pregnancies. Conclusions Heavy alcohol consumption during the second and Methods Participants completed questionnaires detailing alcohol third trimesters was associated with increased risk of preterm consumption during the first trimester and during the second and delivery among pregnant women. third trimesters. Participants were divided into four categories according to alcohol consumption (non-drinkers, consumers of Keywords Alcohol consumption, pregnant women, preterm 1–149 g, 150–299 g and ≥300 g ethanol/week). We examined the delivery, prospective study, the Japan Environment and Children’s effect of alcohol consumption during different stages of pregnancy Study (JECS). on the risk of preterm delivery. Odds ratios (OR) and 95% CI Tweetable abstract Heavy drinking during pregnancy may were calculated relative to non-drinkers using logistic regression. increase the risk of preterm delivery. Main outcome measures Medical record-based preterm delivery. Linked article This article is commented on by SV Sun and TA Results Alcohol consumption during the second and third trimesters, Manuck, p. 1455 in this issue. To view this mini commentary visit but not during the first trimester, was associated with increased risk https://doi.org/10.1111/1471-0528.15918. Please cite this paper as: Ikehara S, Kimura T, Kakigano A, Sato T, Iso H, the Japan Environment Children’s Study Group. Association between maternal alcohol consumption during pregnancy and risk of preterm delivery: the Japan Environment and Children’s Study. BJOG 2019;126:1448–1454. reduced risk of preterm delivery, regardless of the timing Introduction of exposure to alcohol. A recent meta-analysis of 14 Some cohort studies suggest a J-shaped association between cohort and case–control studies also showed that light 1–5 alcohol consumption and the risk of preterm delivery. A drinking of up to 18 g ethanol per day (1.5 drinks per day) previous cohort study showed that light-to-moderate alco- was not linked to preterm delivery. On the other hand, hol consumption during pregnancy was associated with a although the information on the specific term of alcohol consumption during pregnancy was not included, a study composed of approximately 1 220 000 singleton records Study Group members are listed in Appendix 1. 1448 ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Maternal alcohol consumption and preterm delivery reported that prenatal alcohol consumption was positively Japan Environment and Children’s Study (JECS) associated with risk of preterm delivery. Several studies 103 099 pregnancies investigating the effects of light-to-moderate alcohol con- sumption have reported no association with preterm deliv- 9–15 Multiple pregnancies (N = 991) ery. Missing maternal age (N = 116) No firm conclusion with respect to the effect of alcohol consumption during pregnancy on the preterm delivery risk has been reached. Furthermore, no study has examined the 101 992 singleton pregnancies effect of alcohol consumption at different stages of pregnancy on the risk of preterm delivery in a Japanese population. Invalid information at delivery: gestational age Therefore, the association of alcohol consumption during (N = 2233), infant sex (N = 867) Gestational age less than 22 weeks (N = 400) the first trimester and during the second and third trime- Missing alcohol consumption information in sters with preterm delivery risk was investigated using data the first trimester and second/third trimesters from 94 349 pregnant women in a large birth cohort. of pregnancy (N = 916) History of preterm delivery (N = 3227) Methods 94 349 pregnancies with available data Study population The Japan Environment and Children’s Study (JECS), a nationwide birth cohort study, began in January 2011 and recruitment finished in March 2014. In total, 103 099 preg- nancies were registered. Details concerning the JECS project 16,17 Analysis for the first trimester Analysis for the second/third trimesters have been presented in previous articles. The JECS was 93 631 pregnancies 92 780 pregnancies approved by the Institutional Review Board of the Japan National Institute for Environmental Studies, as well as the Figure 1. Participant selection flow chart. ethics committees of all participating institutions. The pre- sent study is based on the jecs-ag-20160424 data set, which history, history of previous pregnancies, infant sex and was released in June 2016 and revised in October 2016. perinatal outcomes, such as gestational duration and birth- Core outcome set and patient involvement are not relevant weight, were collected through data transcription from to this study. The JECS was funded by the Ministry of the 16,17 Environment, Japan. medical records. Data transcription was performed by physicians, nurses, midwives or research coordinators. Diet- Among the 101 992 singleton pregnant women eligible ary information was obtained with a food frequency ques- for the present study, we excluded 3100 individuals who tionnaire. Preterm delivery was defined as delivery between had certain information, such as gestational age and infant 22 and 37 weeks of gestation. We used participant weight sex, unavailable at delivery. An additional 400 women with before pregnancy to calculate maternal body mass index an infant gestational age <22 weeks, 916 women with miss- 2 2 (weight [kg]/height [m ]). ing information on alcohol consumption for both stages of We asked the participants whether they never drank, pregnancy and 3227 women with a history of preterm were past drinkers or were current drinkers to record alco- delivery were also excluded. We subsequently excluded hol consumption during the first trimester. Past and cur- pregnancies with missing alcohol consumption information rent drinkers were asked about the frequency of their at each stage of pregnancy. The analysis of the first trime- alcohol consumption during the 1 year before pregnancy. ster included 93 631 pregnancies, and 92 780 pregnancies They indicated whether they drank almost never, one to were included in the analysis of the second and third tri- three times per month, once or twice per week, three or mesters. (Figure 1) four times per week, five or six times per week or every day. We also recorded the amount of alcohol consumption Data collection per day according to the type of alcoholic beverage. Types Self-administered questionnaires were conducted during of alcohol included sake (rice wine), shochu awamori (white the first trimester and during the second and third trime- spirits), beer, whisky and wine. sters. Information obtained included demographic charac- To assess alcohol consumption during the second and teristics, medical history, socio-economic status, alcohol third trimesters, we asked participants whether they never consumption, smoking, physical activity and psychological drank, had quit drinking before pregnancy, had quit drink- factors. Maternal anthropometric data before pregnancy as well as data on complications during pregnancy, medical ing during early pregnancy or currently drank. Current ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of 1449 Royal College of Obstetricians and Gynaecologists Ikehara et al. drinkers were then asked about the frequency and amount explain the observed association under the condition of the of their alcohol consumption per day as well as the type of measured covariates. alcoholic beverages consumed during pregnancy. We assigned fractions to alcohol consumption frequency cate- Results gories as follows: 0 for almost never, 0.5 for one to three times per month, 1.5 for once or twice per week, 3.5 for Table 1 shows characteristics based on alcohol consump- three or four times per week, 5.5 for five or six times per tion during the first trimester and during the second and week and 7 for participants drinking alcohol every day. third trimesters. In the first trimester, 91.2% of participants The amount of ethanol was calculated in grams as follows: were non-drinkers, 7.5% consumed 1–149 g ethanol per 180 ml sake has 23 g ethanol, 180 ml shochu or awamori week, 0.8% consumed 150–299 g per week, and 0.5% con- has 36 g ethanol, 633 ml beer has 23 g ethanol, 30 ml sumed ≥300 g ethanol per week. The corresponding per- whisky has 10 g ethanol and 60 ml wine has 9 g ethanol. centages of participants in each category during the second Alcohol consumption per week was calculated by multiply- and third trimesters were 98.0% non-drinkers, 1.96% con- ing the frequency of drinking alcohol and the amount of suming 1–149 g ethanol per week, 0.05% consuming 150- ethanol per occasion according to the programme provided 299 g per week, and 0.03% consuming ≥300 g ethanol per by the Japan Public Health Centre-Based Prospective Study week. The percentage of participants delivering preterm for the Next Generation. Participants were categorised was 4.1% for the first-trimester analysis and 3.4% for the according to alcohol consumption into non-drinkers, cur- analysis of the second and third trimesters. rent drinkers of 1–149 g ethanol per week, current drinkers Drinkers of ≥300 g ethanol per week during the first tri- of 150–299 g ethanol per week, and current drinkers of mester were older, more likely to be smokers, multiparous ≥300 g ethanol per week. and exposed to passive smoking, and had higher folate intake and fewer gestational weeks and lower birthweight Statistical analysis infants compared with non-drinkers. Drinkers of ≥300 g Mean values and preterm delivery risk factor prevalence ethanol per week during the second and third trimesters according to alcohol consumption were calculated. The were younger, less likely to be educated, more likely to be odds ratios (ORs) with 95% CI for preterm delivery in smokers or exposed to passive smoking, more likely to have relation to the alcohol consumption categories were esti- previous birth experience, hypertensive disorders of preg- mated using logistic regression. These estimates were nancy, higher physical activity levels and folate intakes, and adjusted for age and other confounding factors including fewer gestational weeks and lower birthweight infants com- residential area (15 regional centres), smoking (never pared with non-drinkers. Drinkers of ≥300 g ethanol per smoked, quit smoking before pregnancy, quit smoking dur- week during the second and third trimesters tended to have ing early pregnancy, currently smoking one to nine cigar- a higher incidence of late preterm delivery. ettes per day or ten cigarettes or more per day), the Table 2 shows the age-adjusted and multivariable- frequency of passive smoking (almost never, 1 day/week, adjusted ORs (95% CI) for preterm delivery based on the 2–6 days/week and every day), body mass index before categories of alcohol consumption in the first trimester and pregnancy, education (junior high school, high school, in the second and third trimesters. Alcohol consumption technical college, vocational school, junior college, univer- during the first trimester was not associated with increased sity or graduate school), physical activity (metabolic equiv- risk of preterm birth, whereas alcohol consumption during alent), history of hypertension and dietary folate intake the second and third trimesters showed a J-shaped associa- (quintiles). We used updated smoking, physical activity tion with the risk of preterm delivery. Light drinking of 1– and dietary folate intake data, which were obtained using 149 g ethanol per week was not significantly associated the questionnaire for the second and third trimesters, in with reduced risk of preterm delivery, whereas heavy drink- the analysis during pregnancy. We excluded participants ing of ≥300 g ethanol per week was associated with a sig- with missing data related to outcome, exposure and biolog- nificant increased risk of preterm delivery compared with ical factors such as maternal age and infant sex from the non-drinkers. Multivariable ORs were 0.78 (95% CI 0.60– analysis. Missing data of confounding factors were included 1.00) and 4.52 (95% CI 1.68–12.2) for light drinking and as categorical variables in the model. SAS 9.4 statistical heavy drinking, respectively. software (SAS Institute Inc., Cary, NC, USA) was used for these analyses. We also used E-value to conduct the sensi- Discussion tivity analysis for unmeasured confounding (E-value calcu- lator: www.evalue-calculator.com/). The E-value estimates Main findings the minimum strength of the association of the unmea- In the large birth cohort study, alcohol consumption during sured confounder with exposure and outcome to fully the first trimester was not associated with risk of preterm 1450 ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists Maternal alcohol consumption and preterm delivery Table 1. Mean and prevalence of characteristics according to alcohol consumption in the first trimester and in the second and third trimesters Non-drinkers Current drinkers (g ethanol/week) P for trend 1–149 150–299 ≥300 Alcohol consumption in the first trimester Persons 85 433 7011 761 426 Age (years) 31.0 32.5 33.3 32.3 <0.001 Body mass index before pregnancy (kg/m ) 21.2 21.3 21.4 21.2 0.28 Education, university or graduate school (%) 21.2 29.3 20.8 14.9 0.43 Smoking in the first trimester (%) 4.7 3.6 11.0 29.1 <0.001 Passive smoking during pregnancy ≥1 day/week (%) 37.7 35.6 48.2 65.3 <0.001 Physical activity before pregnancy (METs*min/day) 410.1 359.3 425.6 474.5 0.26 Dietary folate intake for the past year (µg/day) 277.4 291.5 334.3 403.7 <0.001 Primiparity (%) 42.4 33.9 31.4 34.9 <0.001 Hypertensive disorders of pregnancy (%) 3.1 3.1 3.2 4.2 0.29 Gestational age at delivery (weeks) 38.9 38.8 38.9 38.6 0.003 Late preterm delivery (34 to <37 weeks) (%) 3.4 3.4 3.0 3.8 0.97 Moderate preterm delivery (32 to <34 weeks) (%) 0.4 0.4 0.3 0.5 0.99 Very preterm delivery (<32 weeks) (%) 0.6 0.6 0.6 1.4 0.09 Birthweight (g) 3027 3038 3022 2933 <0.001 Premature rupture of the membranes (%) 8.2 8.4 9.6 9.2 0.19 Spontaneous labour (%) 57.8 59.4 56.3 56.5 0.58 Alcohol consumption in the second and third trimesters Persons 90 893 1814 47 26 Age (years) 31.1 32.3 33.8 30.4 <0.01 Body mass index before pregnancy (kg/m ) 21.2 21.2 21.5 20.9 0.92 Education, university or graduate school (%) 21.9 18.1 4.3 7.7 <0.001 Smoking in the second/third trimesters (%) 4.3 15.9 46.8 40.0 <0.001 Passive smoking during pregnancy ≥1 day/week (%) 37.5 51.4 74.5 60.0 <0.001 Physical activity during pregnancy (METs*min/day) 238.1 278.2 350.6 454.6 0.004 Dietary folate intake during pregnancy (µg/day) 258.3 278.0 306.0 345.3 <0.001 Primiparity (%) 42.1 20.0 6.5 30.8 <0.001 Hypertensive disorders of pregnancy (%) 3.1 2.5 8.5 11.5 0.003 Gestational age at delivery (weeks) 38.9 38.9 38.5 37.8 <0.001 Late preterm delivery (34 to <37 weeks) (%) 3.4 3.2 4.3 15.4 0.003 Moderate preterm delivery (32 to <34 weeks) (%) 0.4 0.2 2.2 0.0 0.54 Very preterm delivery (<32 weeks) (%) 0.5 0.1 0.0 3.8 0.11 Birthweight (g) 3031 3045 2925 2733 <0.001 Premature rupture of the membranes (%) 8.3 7.8 12.8 11.5 0.33 Spontaneous labour (%) 57.8 61.7 48.9 52.0 0.49 delivery, whereas in the second and third trimesters we and risk of preterm delivery in Asian women after adjust- found a J-shaped association between alcohol consumption ment for known confounding factors including passive and risk of preterm delivery. Compared with non-drinkers, smoking during pregnancy and folate intake and physical heavy drinking (≥300 g ethanol per week) during the sec- activity levels before or during pregnancy. We also exam- ond and third trimesters had a three-fold higher risk of ined the risk of preterm delivery associated with maternal preterm delivery, whereas light drinking (1–149 g ethanol alcohol consumption in different stages of pregnancy. The per week) tended to be associated with the lower risk. larger population-based cohort study of 1 220 000 single- tons linked to the Missouri vital statistical data examined Strengths and limitations retrospectively the association because alcohol consumption The main strengths of this study include that it was a large during pregnancy was measured at delivery and did not prospective study with a high response rate under a take the above confounding variables into account. national birth cohort. We first found the association The present study also has several limitations. First, expo- between a wide range of alcohol intakes during pregnancy sure misclassification may have occurred because the ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of 1451 Royal College of Obstetricians and Gynaecologists Ikehara et al. Table 2. Odds ratios (OR) (95% CI) for preterm delivery according to alcohol consumption in the first trimester and in the second and third trimesters Non-drinkers Current drinkers (g ethanol/week) 1–149 150–299 ≥300 Alcohol consumption categories in the first trimester Persons 85 433 7011 761 426 No. of cases 3745 300 30 24 Incidence of preterm delivery 4.4 4.3 3.9 5.6 Age-adjusted OR 1.00 0.93 (0.83–1.05) 0.83 (0.58–1.20) 1.25 (0.83–1.89) Multivariable OR* 1.00 0.97 (0.86–1.10) 0.81 (0.56–1.18) 1.05 (0.69–1.60) Alcohol consumption categories in the second/third trimesters Persons 90 893 1814 47 26 No. of cases 3805 63 3 5 Incidence of preterm delivery 4.2 3.5 6.4 19.2 Age-adjusted OR 1.00 0.79 (0.62–1.02) 1.44 (0.45–4.63) 5.58 (2.10–14.8) Multivariable OR** 1.00 0.78 (0.60–1.00) 1.27 (0.39–4.12) 4.52 (1.68–12.2) *Adjustment for maternal age, area, body mass index before pregnancy, education, smoking in the first trimester, frequency of passive smoking during the pregnancy, physical activity before pregnancy, primiparity and dietary folate intake for the year before pregnancy. **Adjustment for maternal age, area, body mass index before pregnancy, education, physical activity during pregnancy, smoking in the second/ third trimesters, frequency of passive smoking during the pregnancy, primiparity and dietary folate intake during pregnancy. 3,8 information on alcohol consumption during pregnancy was previous and present studies. Excess risk of preterm deliv- collected by self-reported questionnaires. It is difficult to ery was found among American women who consumed five assess alcohol consumption among pregnant women because or more drinks per week and European women who con- many pregnant women refrain from drinking alcohol after sumed ten or more drinks per week, and among Japanese becoming aware of their pregnancy or as pregnancy pro- women who consumed ≥28 drinks per week in the present gresses. We used the food frequency questionnaire validated study. Further studies will be necessary to accumulate epi- in a general population of women, in which the Spearman’s demiological findings and evidence on mechanisms. Fourth, correlation coefficient for alcohol consumption between the we did not examine the associations of spontaneous and food frequency questionnaire and 12-day food records over medically indicated preterm deliveries separately because of four seasons at intervals of approximately 3 months was the small number of heavy drinkers. The previous large 18 8 0.67. As there was non-differential exposure misclassifica- study using the Missouri vital statistical data found tion, the real association would become stronger. Second, increased risk of both outcomes associated with heavy drink- we could not examine the associations of alcohol consump- ing. Further work is needed for a detailed understanding of tion patterns such as weekend or binge drinking during the effects of alcohol consumption on spontaneous and pregnancy with risk of preterm delivery because we did not medically indicated preterm delivery. Finally, the associa- collect that information. A previous study reported that tions were adjusted for potential confounding variables, but binge drinking (five or more units per occasion) before we cannot exclude the possibility that unmeasured con- pregnancy, during the first trimester or during the second founding may have affected the findings. We conducted the trimester was not associated with an excess risk of preterm sensitivity analysis for the unmeasured confounders by E- delivery. The Screening for Pregnancy Endpoints (SCOPE) value calculation. The calculated E-value for point estimate study also showed no association between binge drinking was 8.51, so that the observed association would be unlikely before 15 weeks of gestation and risk of adverse pregnancy to disappear with unmeasured confounders. outcomes, including spontaneous preterm delivery. Third, east Asians are commonly intolerant of alcohol due to the Interpretation larger prevalence of less active or inactive forms of aldehyde Our finding of a J-shaped relationship between alcohol con- dehydrogenase-2 encoded by ALDH2*1/*2 or ALDH2*2/*2 sumption and risk of preterm delivery is consistent with the 20 3 than that found in Caucasians. Therefore, east Asians are result from the Danish pregnancy cohort study. That Dan- more likely to accumulate acetaldehyde and suffer from ish cohort study of 18 228 singleton pregnancies showed 21–23 alcohol-related diseases. However, the racial difference that ten or more drinks per week at 16 and 30 weeks of ges- in alcohol metabolism did not meet the findings from tation produced 2.9 and 3.6 times higher risks of preterm 1452 ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists Maternal alcohol consumption and preterm delivery delivery, respectively, whereas the consumption of one to Conclusion two drinks per week at 30 weeks of gestation was associated with a 31% lower risk of preterm delivery compared with In conclusion, heavy alcohol consumption in the second women who consumed less than one drink per week. and third trimesters was associated with increased risk of As for mechanisms of high alcohol consumption and risk preterm delivery among pregnant women. of preterm delivery, alcohol may induce preterm delivery through increased secretion of prostaglandins, which Disclosure of interests enhances uterine contractions. Prostaglandins also None to declare. Completed disclosure of interest forms are increase cyclic 3ʹ,5ʹ-adenosine monophosphate activity, available to view online as supporting information. which involves decreased cell division. In animal experi- ments, increased alcohol intake also induced increased sev- Contribution to authorship ere intravascular coagulation and decreased blood flow in SI, TK, AK, TS and HI contributed substantially to the concep- the placenta. According to a previous report from our tion, design, participant recruitment and data collection of the cohort, alcohol consumption (≥150 g ethanol/week) in the present study. SI and TK were involved in data analysis. SI and second and third trimesters was associated with increased HI drafted the manuscript. All authors were involved in inter- risk of hypertensive disorders of pregnancy, which is one of preting the data and critically reviewing manuscript drafts. All the risk factors for preterm delivery. authors gave approval of the final version of the manuscript. There has been no conclusive biological mechanism pro- Details of ethics approval posed for the reduced risk of preterm delivery associated The JECS was approved by the Institutional Review Board with light drinking. A previous study suggested the healthy of the Japan National Institute for Environmental Studies drinker effect in explaining the association. In the present (date of approval: 9 August 2010 and approval number: study, light drinkers during the second and third trimesters 2010-2R), as well as the Ethics Committees of all partici- had fewer hypertensive disorders. The effect of light alcohol pating institutions. consumption during pregnancy should be interpreted cau- tiously in consideration of other adverse outcomes such as Funding fetal alcohol syndrome, multiple morbidities and develop- The JECS was funded by the Ministry of the Environment, mental disorders. Japan (direct funding, no funding IDs available). We found no association between alcohol consumption in the first trimester and risk of preterm delivery. The effects of Acknowledgements different timings of alcohol consumption on the risk of pre- We are grateful to all JECS participants and all individuals term delivery remain controversial. The Danish pregnancy involved in data collection. JECS was funded by the Japa- cohort study showed singleton mothers consuming ten or nese Ministry of the Environment. The findings and con- more drinks per week at 16 weeks of gestation was associated clusions of this paper are solely the responsibility of the with increased risk of preterm delivery compared with those authors and do not represent official views of the above consuming less than one drink per week (OR 2.93, 95% CI government agency. 1.52–5.63), as with ten or more drinks per week at 30 weeks of gestation (OR 3.56, 95% CI 1.78–7.13). A case–control study of 175 singleton mothers with preterm deliveries and References 313 singleton mothers with full-term deliveries showed that 1 Albertsen K, Andersen AM, Olsen J, Grønbaek M. Alcohol 14 or more drinks per week in any trimester was associated consumption during pregnancy and the risk of preterm delivery. Am with a three-fold increase in the risk of preterm delivery J Epidemiol 2004;159:155–61. based on interviews during the postpartum hospital stay. 2 McDonald AD, Armstrong BG, Sloan M. Cigarette, alcohol, and On the other hand, a prospective study consisting of 5628 coffee consumption and prematurity. Am J Public Health 1992;82:87–90. nulliparous pregnant women (the SCOPE study) showed no 3 Kesmodel U, Olsen SF, Secher NJ. Does alcohol increase the risk of association between consuming alcohol before 15 weeks of preterm delivery? Epidemiology 2000;11:512–8. gestation with spontaneous preterm delivery or other adverse 4 Shiono PH, Klebanoff MA, Rhoads GG. Smoking and drinking during outcomes such as pre-eclampsia and infants being small for pregnancy. Their effects on preterm birth. JAMA 1986;255:82–4. their gestational age or having a low birthweight. A study 5 Lazzaroni F, Bonassi S, Magnani M, Calvi A, Repetto E, Serra F, et al. Moderate maternal drinking and outcome of pregnancy. Eur J of 3447 pregnant women in the Netherlands reported no Epidemiol 1993;9:599–606. association between alcohol consumption in each trimester 6 Lundsberg LS, Illuzzi JL, Belanger K, Triche EW, Bracken MB. Low- and the risk of preterm delivery. Further study is necessary to-moderate prenatal alcohol consumption and the risk of selected to determine the effects of alcohol consumption at different birth outcomes: a prospective cohort study. Ann Epidemiol times during pregnancy on the risk of preterm delivery. 2015;25:46–54. ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of 1453 Royal College of Obstetricians and Gynaecologists Ikehara et al. 7 Patra J, Bakker R, Irving H, Jaddoe VW, Malini S, Rehm J. Dose– 23 Chen CH, Ferreira JC, Gross ER, Mochly-Rosen D. Targeting response relationship between alcohol consumption before and aldehyde dehydrogenase 2: new therapeutic opportunities. Physiol during pregnancy and the risks of low birthweight, preterm birth Rev 2014;94:1–34. and small for gestational age (SGA) – a systematic review and meta- 24 Anton RF, Becker HC, Randall CL. Ethanol increases PGE and analyses. BJOG 2011;118:1411–21. thromboxane production in mouse pregnant uterine tissue. Life Sci 8 Aliyu MH, Lynch O, Belogolovkin V, Zoorob R, Salihu HM. Maternal 1990;46:1145–53. alcohol use and medically indicated vs. spontaneous preterm birth 25 Pennington S. Ethanol-induced growth inhibition: the role of cyclic outcomes: a population-based study. Eur J Public Health AMP-dependent protein kinase. Alcohol Clin Exp Res 1988;12:125–9. 2010;20:582–7. 26 Kennedy LA. Changes in the term mouse placenta associated with 9 Cooper DL, Petherick ES, Wright J. The association between binge maternal alcohol consumption and fetal growth deficits. Am J drinking and birth outcomes: results from the Born in Bradford Obstet Gynecol 1984;149:518–22. cohort study. J Epidemiol Community Health 2013;67:821–8. 27 Jones PJ, Leichter J, Lee M. Placental blood flow in rats fed alcohol 10 McCarthy FP, OʼKeeffe LM, Khashan AS, North RA, Poston L, before and during gestation. Life Sci 1981;29:1153–9. McCowan LM, et al. Association between maternal alcohol 28 Iwama N, Metoki H, Nishigori H, Mizuno S, Takahashi F, Tanaka K, consumption in early pregnancy and pregnancy outcomes. Obstet et al. Association between alcohol consumption during pregnancy Gynecol 2013;122:830–7. and hypertensive disorders of pregnancy in Japan: the Japan 11 Peacock JL, Bland JM, Anderson HR. Preterm delivery: effects of Environment and Children’s Study. Hypertens Res 2019;42:85–94. socioeconomic factors, psychological stress, smoking, alcohol, and 29 Berkowitz GS, Holford TR, Berkowitz RL. Effects of cigarette caffeine. BMJ 1995;311:531–5. smoking, alcohol, coffee and tea consumption on preterm delivery. 12 Verkerk PH, van Noord-Zaadstra BM, Florey CD, de Jonge GA, Early Hum Dev 1982;7:239–50. Verloove-Vanhorick SP. The effect of moderate maternal alcohol consumption on birth weight and gestational age in a low risk Appendix 1 population. Early Hum Dev 1993;32:121–9. 13 Jaddoe VW, Bakker R, Hofman A, Mackenbach JP, Moll HA, Members of JECS as of 2017 (principal investigator, Toshi- Steegers EA, et al. Moderate alcohol consumption during pregnancy hiro Kawamoto): Hirohisa Saito (National Centre for Child and the risk of low birth weight and preterm birth. The generation R study. Ann Epidemiol 2007;17:834–40. Health and Development, Tokyo, Japan), Reiko Kishi (Hok- 14 Smith LK, Draper ES, Evans TA, Field DJ, Johnson SJ, Manktelow kaido Regional Centre for JECS, Hokkaido University, Hok- BN, et al. Associations between late and moderately preterm kaido, Japan), Nobuo Yaegashi (Miyagi Regional Centre for birth and smoking, alcohol, drug use and diet: a population- JECS, Tohoku University, Sendai, Japan), Koichi Hashimoto based case–cohort study. Arch Dis Child Fetal Neonatal Ed 2015;100:F486–91. (Fukushima Regional Centre for JECS, Fukushima Medical 15 Lundsberg LS, Bracken MB, Saftlas AF. Low-to-moderate gestational University, Fukushima, Japan), Chisato Mori (Chiba Regio- alcohol use and intrauterine growth retardation, low birthweight, nal Centre for JECS, Chiba University, Chiba, Japan), Shui- and preterm delivery. Ann Epidemiol 1997;7:498–508. chi Ito (Kanagawa Regional Centre for JECS, Yokohama 16 Kawamoto T, Nitta H, Murata K, Toda E, Tsukamoto N, Hasegawa City University, Kanagawa, Japan), Zentaro Yamagata M, et al. Rationale and study design of the Japan Environment and Children’s Study (JECS). BMC Public Health 2014;14:25. (Koshin Regional Centre for JECS, University of Yamanashi, 17 Michikawa T, Nitta H, Nakayama SF, Yamazaki S, Isobe T, Tamura Yamanashi, Japan), Hidekuni Inadera (Toyama Regional K, et al. Baseline profile of participants in the Japan Environment Centre for JECS, University of Toyama, Toyama, Japan), and Children’s Study (JECS). J Epidemiol 2018;28:99–104. Michihiro Kamijima (Aichi Regional Centre for JECS, 18 Yokoyama Y, Takachi R, Ishihara J, Ishii Y, Sasazuki S, Sawada N, Nagoya City University, Aichi, Japan), Takeo Nakayama et al. Validity of short and long self-administered food frequency (Kyoto Regional Centre for JECS, Kyoto University, Kyoto, questionnaires in ranking dietary intake in middle-aged and elderly Japanese in the Japan Public Health Center-based prospective study Japan), Hiroyasu Iso (Osaka Regional Centre for JECS, for the next generation (JPHC-NEXT) protocol area. J Epidemiol Osaka University, Osaka, Japan), Masayuki Shima (Hyogo 2016;26:420–32. Regional Centre for JECS, Hyogo College of Medicine, 19 VanderWeele TJ, Ding P. Sensitivity analysis in observational research: Hyogo, Japan), Yasuaki Hirooka (Tottori Regional Centre introducing the E-Value. Ann Intern Med 2017;167:268–74. for JECS, Tottori University, Tottori, Japan), Narufumi 20 Hendershot CS, Collins SE, George WH, Wall TL, McCarthy DM, Liang T, et al. Associations of ALDH2 and ADH1B genotypes with Suganuma (Kochi Regional Centre for JECS, Kochi Univer- alcohol-related phenotypes in Asian young adults. Alcohol Clin Exp sity, Kochi, Japan), Koichi Kusuhara (Fukuoka Regional Res 2009;33:839–47. Centre for JECS, Kyushu University, Fukuoka, Japan) and 21 Ishioka K, Masaoka H, Ito H, Oze I, Ito S, Tajika M, et al. Association Takahiko Katoh (South Kyushu/Okinawa Regional Centre between ALDH2 and ADH1B polymorphisms, alcohol drinking and gastric cancer: a replication and mediation analysis. Gastric Cancer for JECS, Kumamoto University, Kumamoto, Japan). 2018;21:936–45. 22 Oze I, Matsuo K, Hosono S, Ito H, Kawase T, Watanabe M, et al. Comparison between self-reported facial flushing after alcohol consumption and ALDH2 Glu504Lys polymorphism for risk of upper aerodigestive tract cancer in a Japanese population. Cancer Sci 2010;101:1875–80. 1454 ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists Maternal alcohol consumption and preterm delivery Alcohol in pregnancy: not recommended at any gestational age a a,b SV Sun, TA Manuck Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Institute for Environmental Health Solutions, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Linked article: This is a mini commentary on S Ikehara et al., pp. 1448–1454 in this issue. To view this article visit https://doi.org/10.1111/1471-0528.15899 Published Online 17 September 2019. Preterm birth remains a multifactorial, caution. The stigma of alcohol con- health indicators. Lastly, even among worldwide problem. Though there are sumption in pregnancy lends itself to heavy drinkers, statistical factors substantial risk of underestimation on should also be considered, particularly multiple established risk factors for self-report. Even among alcohol drin- given the size of the cohort, as statisti- preterm birth (e.g. previous preterm kers, data were collapsed into weekly cal significance is more easily achieved. birth, short cervix), the association between maternal alcohol consump- consumption, reducing the ability to Only 0.08% (n = 73) of women in this tion and prematurity is less clear, with evaluate binge drinking versus daily cohort had moderate or heavy alcohol risk ratios ranging from 0.66 (95% CI lower levels of drinking. These data consumption in the second and third are limited to a homogeneous Japanese trimesters. Of these, just eight deliv- 0.52–0.84) to 1.34 (95% CI 1.28–1.41) population, a group more likely to ered preterm. (Strandberg-Larsen et al. Eur J Epi- have a genetic predisposition to alco- demiol 2017;32:751–64; Aliyu et al. While placing these results in the hol intolerance, which probably ‘se- Eur J Public Health 2010;20:582–7). context of current clinical recommen- lected’ for individuals who cannot dations, it is crucial to remember that Ikehara and colleagues (Ikehara tolerate alcohol, and who had an over- alcohol is an established teratogen and et al. BJOG 2019;126:1448–54) present all low rate of prematurity (4.2%). findings from the Japan Environment any degree of alcohol use during preg- Further, women with a history of and Children’s Study, a large nation- nancy can be harmful, with potential adverse pregnancy outcomes may be wide birth cohort. They reported a irreversible effects on fetal brain struc- less likely to consume substances, but ture and function and consequently on J-shaped association between the level because of their pregnancy history are short- and long-term fetal and child- of alcohol consumption in the second more likely to deliver preterm, biasing hood neurodevelopment (Williams and third trimesters and preterm the results against the abstainers. et al. Pediatrics 2015;136:e1395–406). birth; specifically, a lower risk of pre- Though women with a previous pre- maturity (adjusted odds ratio [aOR] In conclusion, these data under- term birth were excluded from analy- 0.78, 95% CI 0.60–1.00) in light drin- score the importance of screening for sis, no additional information was kers but an increased risk of prematu- alcohol consumption across gestation, provided regarding pregnancy history rity (aOR 4.52, 95% CI 1.68–12.2) in and reinforce continued recommenda- or obstetric risk factors. A sensitivity heavy drinkers (women consuming tions for abstention from alcohol dur- analysis evaluating whether the >300 g alcohol/week, ~21 standard ing pregnancy. observed effects – particularly among drinks). No relationship between first- light drinkers – persist among nulli- trimester alcohol exposure and prema- Disclosure of interests paras or those with previous uncom- turity was found. A major study Nothing to declare. Completed disclo- plicated pregnancies could address this strength is its size, as over 90 000 sure of interest forms are available to specific confounder. Additionally, pre- pregnancies were included (Ikehara view online as supporting information. maturity is used as a surrogate end et al. BJOG 2019;126:1448–54). point for the more important – albeit However, limitations abound. These Funding more difficult to study – long-term data – particularly the suggested lower outcomes of cognitive function, neu- Funded, in part, by NIH R01- rate of prematurity among light rodevelopment and other life-long MD011609 (Manuck).& drinkers – should be interpreted with ª 2019 Royal College of Obstetricians and Gynaecologists 1455 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Bjog Pubmed Central

Association between maternal alcohol consumption during pregnancy and risk of preterm delivery: the Japan Environment and Children's Study

Bjog , Volume 126 (12) – Aug 25, 2019

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© 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists.
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Abstract

DOI: 10.1111/1471-0528.15899 Epidemiology www.bjog.org Association between maternal alcohol consumption during pregnancy and risk of preterm delivery: the Japan Environment and Children’s Study a b c d a S Ikehara, T Kimura, A Kakigano, T Sato, H Iso, the Japan Environment Children’s Study Group a b Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, Suita-shi, Japan Department of Public Health, Hokkaido University Graduate School of Medicine, Sapporo, Japan Department of Obstetrics and Gynaecology, Osaka University Graduate School of Medicine, Suita-shi, Japan Osaka Maternal and Child Health Information Centre, Osaka Women’s and Children’s Hospital, Izumi, Japan Correspondence: S Ikehara, Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-shi, Osaka 565-0871, Japan. Email: s-ikehara@pbhel.med.osaka-u.ac.jp Accepted 22 July 2019. Published Online 25 August 2019. Objective To examine the association between maternal alcohol of preterm delivery. Heavy alcohol consumption (≥300 g ethanol/ consumption during pregnancy and the risk of preterm delivery. week) during the second and third trimesters was associated with a four-fold higher risk compared with non-drinkers (multivariable OR Design Prospective cohort study. 4.52; 95% CI 1.68–12.2). Light alcohol consumption (1–149 g Setting The Japan Environment and Children’s Study (JECS). ethanol/week) tended to be associated with lower risk of preterm delivery (multivariable OR 0.78; 95% CI 0.60–1.00). Population A total of 94 349 singleton pregnancies. Conclusions Heavy alcohol consumption during the second and Methods Participants completed questionnaires detailing alcohol third trimesters was associated with increased risk of preterm consumption during the first trimester and during the second and delivery among pregnant women. third trimesters. Participants were divided into four categories according to alcohol consumption (non-drinkers, consumers of Keywords Alcohol consumption, pregnant women, preterm 1–149 g, 150–299 g and ≥300 g ethanol/week). We examined the delivery, prospective study, the Japan Environment and Children’s effect of alcohol consumption during different stages of pregnancy Study (JECS). on the risk of preterm delivery. Odds ratios (OR) and 95% CI Tweetable abstract Heavy drinking during pregnancy may were calculated relative to non-drinkers using logistic regression. increase the risk of preterm delivery. Main outcome measures Medical record-based preterm delivery. Linked article This article is commented on by SV Sun and TA Results Alcohol consumption during the second and third trimesters, Manuck, p. 1455 in this issue. To view this mini commentary visit but not during the first trimester, was associated with increased risk https://doi.org/10.1111/1471-0528.15918. Please cite this paper as: Ikehara S, Kimura T, Kakigano A, Sato T, Iso H, the Japan Environment Children’s Study Group. Association between maternal alcohol consumption during pregnancy and risk of preterm delivery: the Japan Environment and Children’s Study. BJOG 2019;126:1448–1454. reduced risk of preterm delivery, regardless of the timing Introduction of exposure to alcohol. A recent meta-analysis of 14 Some cohort studies suggest a J-shaped association between cohort and case–control studies also showed that light 1–5 alcohol consumption and the risk of preterm delivery. A drinking of up to 18 g ethanol per day (1.5 drinks per day) previous cohort study showed that light-to-moderate alco- was not linked to preterm delivery. On the other hand, hol consumption during pregnancy was associated with a although the information on the specific term of alcohol consumption during pregnancy was not included, a study composed of approximately 1 220 000 singleton records Study Group members are listed in Appendix 1. 1448 ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Maternal alcohol consumption and preterm delivery reported that prenatal alcohol consumption was positively Japan Environment and Children’s Study (JECS) associated with risk of preterm delivery. Several studies 103 099 pregnancies investigating the effects of light-to-moderate alcohol con- sumption have reported no association with preterm deliv- 9–15 Multiple pregnancies (N = 991) ery. Missing maternal age (N = 116) No firm conclusion with respect to the effect of alcohol consumption during pregnancy on the preterm delivery risk has been reached. Furthermore, no study has examined the 101 992 singleton pregnancies effect of alcohol consumption at different stages of pregnancy on the risk of preterm delivery in a Japanese population. Invalid information at delivery: gestational age Therefore, the association of alcohol consumption during (N = 2233), infant sex (N = 867) Gestational age less than 22 weeks (N = 400) the first trimester and during the second and third trime- Missing alcohol consumption information in sters with preterm delivery risk was investigated using data the first trimester and second/third trimesters from 94 349 pregnant women in a large birth cohort. of pregnancy (N = 916) History of preterm delivery (N = 3227) Methods 94 349 pregnancies with available data Study population The Japan Environment and Children’s Study (JECS), a nationwide birth cohort study, began in January 2011 and recruitment finished in March 2014. In total, 103 099 preg- nancies were registered. Details concerning the JECS project 16,17 Analysis for the first trimester Analysis for the second/third trimesters have been presented in previous articles. The JECS was 93 631 pregnancies 92 780 pregnancies approved by the Institutional Review Board of the Japan National Institute for Environmental Studies, as well as the Figure 1. Participant selection flow chart. ethics committees of all participating institutions. The pre- sent study is based on the jecs-ag-20160424 data set, which history, history of previous pregnancies, infant sex and was released in June 2016 and revised in October 2016. perinatal outcomes, such as gestational duration and birth- Core outcome set and patient involvement are not relevant weight, were collected through data transcription from to this study. The JECS was funded by the Ministry of the 16,17 Environment, Japan. medical records. Data transcription was performed by physicians, nurses, midwives or research coordinators. Diet- Among the 101 992 singleton pregnant women eligible ary information was obtained with a food frequency ques- for the present study, we excluded 3100 individuals who tionnaire. Preterm delivery was defined as delivery between had certain information, such as gestational age and infant 22 and 37 weeks of gestation. We used participant weight sex, unavailable at delivery. An additional 400 women with before pregnancy to calculate maternal body mass index an infant gestational age <22 weeks, 916 women with miss- 2 2 (weight [kg]/height [m ]). ing information on alcohol consumption for both stages of We asked the participants whether they never drank, pregnancy and 3227 women with a history of preterm were past drinkers or were current drinkers to record alco- delivery were also excluded. We subsequently excluded hol consumption during the first trimester. Past and cur- pregnancies with missing alcohol consumption information rent drinkers were asked about the frequency of their at each stage of pregnancy. The analysis of the first trime- alcohol consumption during the 1 year before pregnancy. ster included 93 631 pregnancies, and 92 780 pregnancies They indicated whether they drank almost never, one to were included in the analysis of the second and third tri- three times per month, once or twice per week, three or mesters. (Figure 1) four times per week, five or six times per week or every day. We also recorded the amount of alcohol consumption Data collection per day according to the type of alcoholic beverage. Types Self-administered questionnaires were conducted during of alcohol included sake (rice wine), shochu awamori (white the first trimester and during the second and third trime- spirits), beer, whisky and wine. sters. Information obtained included demographic charac- To assess alcohol consumption during the second and teristics, medical history, socio-economic status, alcohol third trimesters, we asked participants whether they never consumption, smoking, physical activity and psychological drank, had quit drinking before pregnancy, had quit drink- factors. Maternal anthropometric data before pregnancy as well as data on complications during pregnancy, medical ing during early pregnancy or currently drank. Current ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of 1449 Royal College of Obstetricians and Gynaecologists Ikehara et al. drinkers were then asked about the frequency and amount explain the observed association under the condition of the of their alcohol consumption per day as well as the type of measured covariates. alcoholic beverages consumed during pregnancy. We assigned fractions to alcohol consumption frequency cate- Results gories as follows: 0 for almost never, 0.5 for one to three times per month, 1.5 for once or twice per week, 3.5 for Table 1 shows characteristics based on alcohol consump- three or four times per week, 5.5 for five or six times per tion during the first trimester and during the second and week and 7 for participants drinking alcohol every day. third trimesters. In the first trimester, 91.2% of participants The amount of ethanol was calculated in grams as follows: were non-drinkers, 7.5% consumed 1–149 g ethanol per 180 ml sake has 23 g ethanol, 180 ml shochu or awamori week, 0.8% consumed 150–299 g per week, and 0.5% con- has 36 g ethanol, 633 ml beer has 23 g ethanol, 30 ml sumed ≥300 g ethanol per week. The corresponding per- whisky has 10 g ethanol and 60 ml wine has 9 g ethanol. centages of participants in each category during the second Alcohol consumption per week was calculated by multiply- and third trimesters were 98.0% non-drinkers, 1.96% con- ing the frequency of drinking alcohol and the amount of suming 1–149 g ethanol per week, 0.05% consuming 150- ethanol per occasion according to the programme provided 299 g per week, and 0.03% consuming ≥300 g ethanol per by the Japan Public Health Centre-Based Prospective Study week. The percentage of participants delivering preterm for the Next Generation. Participants were categorised was 4.1% for the first-trimester analysis and 3.4% for the according to alcohol consumption into non-drinkers, cur- analysis of the second and third trimesters. rent drinkers of 1–149 g ethanol per week, current drinkers Drinkers of ≥300 g ethanol per week during the first tri- of 150–299 g ethanol per week, and current drinkers of mester were older, more likely to be smokers, multiparous ≥300 g ethanol per week. and exposed to passive smoking, and had higher folate intake and fewer gestational weeks and lower birthweight Statistical analysis infants compared with non-drinkers. Drinkers of ≥300 g Mean values and preterm delivery risk factor prevalence ethanol per week during the second and third trimesters according to alcohol consumption were calculated. The were younger, less likely to be educated, more likely to be odds ratios (ORs) with 95% CI for preterm delivery in smokers or exposed to passive smoking, more likely to have relation to the alcohol consumption categories were esti- previous birth experience, hypertensive disorders of preg- mated using logistic regression. These estimates were nancy, higher physical activity levels and folate intakes, and adjusted for age and other confounding factors including fewer gestational weeks and lower birthweight infants com- residential area (15 regional centres), smoking (never pared with non-drinkers. Drinkers of ≥300 g ethanol per smoked, quit smoking before pregnancy, quit smoking dur- week during the second and third trimesters tended to have ing early pregnancy, currently smoking one to nine cigar- a higher incidence of late preterm delivery. ettes per day or ten cigarettes or more per day), the Table 2 shows the age-adjusted and multivariable- frequency of passive smoking (almost never, 1 day/week, adjusted ORs (95% CI) for preterm delivery based on the 2–6 days/week and every day), body mass index before categories of alcohol consumption in the first trimester and pregnancy, education (junior high school, high school, in the second and third trimesters. Alcohol consumption technical college, vocational school, junior college, univer- during the first trimester was not associated with increased sity or graduate school), physical activity (metabolic equiv- risk of preterm birth, whereas alcohol consumption during alent), history of hypertension and dietary folate intake the second and third trimesters showed a J-shaped associa- (quintiles). We used updated smoking, physical activity tion with the risk of preterm delivery. Light drinking of 1– and dietary folate intake data, which were obtained using 149 g ethanol per week was not significantly associated the questionnaire for the second and third trimesters, in with reduced risk of preterm delivery, whereas heavy drink- the analysis during pregnancy. We excluded participants ing of ≥300 g ethanol per week was associated with a sig- with missing data related to outcome, exposure and biolog- nificant increased risk of preterm delivery compared with ical factors such as maternal age and infant sex from the non-drinkers. Multivariable ORs were 0.78 (95% CI 0.60– analysis. Missing data of confounding factors were included 1.00) and 4.52 (95% CI 1.68–12.2) for light drinking and as categorical variables in the model. SAS 9.4 statistical heavy drinking, respectively. software (SAS Institute Inc., Cary, NC, USA) was used for these analyses. We also used E-value to conduct the sensi- Discussion tivity analysis for unmeasured confounding (E-value calcu- lator: www.evalue-calculator.com/). The E-value estimates Main findings the minimum strength of the association of the unmea- In the large birth cohort study, alcohol consumption during sured confounder with exposure and outcome to fully the first trimester was not associated with risk of preterm 1450 ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists Maternal alcohol consumption and preterm delivery Table 1. Mean and prevalence of characteristics according to alcohol consumption in the first trimester and in the second and third trimesters Non-drinkers Current drinkers (g ethanol/week) P for trend 1–149 150–299 ≥300 Alcohol consumption in the first trimester Persons 85 433 7011 761 426 Age (years) 31.0 32.5 33.3 32.3 <0.001 Body mass index before pregnancy (kg/m ) 21.2 21.3 21.4 21.2 0.28 Education, university or graduate school (%) 21.2 29.3 20.8 14.9 0.43 Smoking in the first trimester (%) 4.7 3.6 11.0 29.1 <0.001 Passive smoking during pregnancy ≥1 day/week (%) 37.7 35.6 48.2 65.3 <0.001 Physical activity before pregnancy (METs*min/day) 410.1 359.3 425.6 474.5 0.26 Dietary folate intake for the past year (µg/day) 277.4 291.5 334.3 403.7 <0.001 Primiparity (%) 42.4 33.9 31.4 34.9 <0.001 Hypertensive disorders of pregnancy (%) 3.1 3.1 3.2 4.2 0.29 Gestational age at delivery (weeks) 38.9 38.8 38.9 38.6 0.003 Late preterm delivery (34 to <37 weeks) (%) 3.4 3.4 3.0 3.8 0.97 Moderate preterm delivery (32 to <34 weeks) (%) 0.4 0.4 0.3 0.5 0.99 Very preterm delivery (<32 weeks) (%) 0.6 0.6 0.6 1.4 0.09 Birthweight (g) 3027 3038 3022 2933 <0.001 Premature rupture of the membranes (%) 8.2 8.4 9.6 9.2 0.19 Spontaneous labour (%) 57.8 59.4 56.3 56.5 0.58 Alcohol consumption in the second and third trimesters Persons 90 893 1814 47 26 Age (years) 31.1 32.3 33.8 30.4 <0.01 Body mass index before pregnancy (kg/m ) 21.2 21.2 21.5 20.9 0.92 Education, university or graduate school (%) 21.9 18.1 4.3 7.7 <0.001 Smoking in the second/third trimesters (%) 4.3 15.9 46.8 40.0 <0.001 Passive smoking during pregnancy ≥1 day/week (%) 37.5 51.4 74.5 60.0 <0.001 Physical activity during pregnancy (METs*min/day) 238.1 278.2 350.6 454.6 0.004 Dietary folate intake during pregnancy (µg/day) 258.3 278.0 306.0 345.3 <0.001 Primiparity (%) 42.1 20.0 6.5 30.8 <0.001 Hypertensive disorders of pregnancy (%) 3.1 2.5 8.5 11.5 0.003 Gestational age at delivery (weeks) 38.9 38.9 38.5 37.8 <0.001 Late preterm delivery (34 to <37 weeks) (%) 3.4 3.2 4.3 15.4 0.003 Moderate preterm delivery (32 to <34 weeks) (%) 0.4 0.2 2.2 0.0 0.54 Very preterm delivery (<32 weeks) (%) 0.5 0.1 0.0 3.8 0.11 Birthweight (g) 3031 3045 2925 2733 <0.001 Premature rupture of the membranes (%) 8.3 7.8 12.8 11.5 0.33 Spontaneous labour (%) 57.8 61.7 48.9 52.0 0.49 delivery, whereas in the second and third trimesters we and risk of preterm delivery in Asian women after adjust- found a J-shaped association between alcohol consumption ment for known confounding factors including passive and risk of preterm delivery. Compared with non-drinkers, smoking during pregnancy and folate intake and physical heavy drinking (≥300 g ethanol per week) during the sec- activity levels before or during pregnancy. We also exam- ond and third trimesters had a three-fold higher risk of ined the risk of preterm delivery associated with maternal preterm delivery, whereas light drinking (1–149 g ethanol alcohol consumption in different stages of pregnancy. The per week) tended to be associated with the lower risk. larger population-based cohort study of 1 220 000 single- tons linked to the Missouri vital statistical data examined Strengths and limitations retrospectively the association because alcohol consumption The main strengths of this study include that it was a large during pregnancy was measured at delivery and did not prospective study with a high response rate under a take the above confounding variables into account. national birth cohort. We first found the association The present study also has several limitations. First, expo- between a wide range of alcohol intakes during pregnancy sure misclassification may have occurred because the ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of 1451 Royal College of Obstetricians and Gynaecologists Ikehara et al. Table 2. Odds ratios (OR) (95% CI) for preterm delivery according to alcohol consumption in the first trimester and in the second and third trimesters Non-drinkers Current drinkers (g ethanol/week) 1–149 150–299 ≥300 Alcohol consumption categories in the first trimester Persons 85 433 7011 761 426 No. of cases 3745 300 30 24 Incidence of preterm delivery 4.4 4.3 3.9 5.6 Age-adjusted OR 1.00 0.93 (0.83–1.05) 0.83 (0.58–1.20) 1.25 (0.83–1.89) Multivariable OR* 1.00 0.97 (0.86–1.10) 0.81 (0.56–1.18) 1.05 (0.69–1.60) Alcohol consumption categories in the second/third trimesters Persons 90 893 1814 47 26 No. of cases 3805 63 3 5 Incidence of preterm delivery 4.2 3.5 6.4 19.2 Age-adjusted OR 1.00 0.79 (0.62–1.02) 1.44 (0.45–4.63) 5.58 (2.10–14.8) Multivariable OR** 1.00 0.78 (0.60–1.00) 1.27 (0.39–4.12) 4.52 (1.68–12.2) *Adjustment for maternal age, area, body mass index before pregnancy, education, smoking in the first trimester, frequency of passive smoking during the pregnancy, physical activity before pregnancy, primiparity and dietary folate intake for the year before pregnancy. **Adjustment for maternal age, area, body mass index before pregnancy, education, physical activity during pregnancy, smoking in the second/ third trimesters, frequency of passive smoking during the pregnancy, primiparity and dietary folate intake during pregnancy. 3,8 information on alcohol consumption during pregnancy was previous and present studies. Excess risk of preterm deliv- collected by self-reported questionnaires. It is difficult to ery was found among American women who consumed five assess alcohol consumption among pregnant women because or more drinks per week and European women who con- many pregnant women refrain from drinking alcohol after sumed ten or more drinks per week, and among Japanese becoming aware of their pregnancy or as pregnancy pro- women who consumed ≥28 drinks per week in the present gresses. We used the food frequency questionnaire validated study. Further studies will be necessary to accumulate epi- in a general population of women, in which the Spearman’s demiological findings and evidence on mechanisms. Fourth, correlation coefficient for alcohol consumption between the we did not examine the associations of spontaneous and food frequency questionnaire and 12-day food records over medically indicated preterm deliveries separately because of four seasons at intervals of approximately 3 months was the small number of heavy drinkers. The previous large 18 8 0.67. As there was non-differential exposure misclassifica- study using the Missouri vital statistical data found tion, the real association would become stronger. Second, increased risk of both outcomes associated with heavy drink- we could not examine the associations of alcohol consump- ing. Further work is needed for a detailed understanding of tion patterns such as weekend or binge drinking during the effects of alcohol consumption on spontaneous and pregnancy with risk of preterm delivery because we did not medically indicated preterm delivery. Finally, the associa- collect that information. A previous study reported that tions were adjusted for potential confounding variables, but binge drinking (five or more units per occasion) before we cannot exclude the possibility that unmeasured con- pregnancy, during the first trimester or during the second founding may have affected the findings. We conducted the trimester was not associated with an excess risk of preterm sensitivity analysis for the unmeasured confounders by E- delivery. The Screening for Pregnancy Endpoints (SCOPE) value calculation. The calculated E-value for point estimate study also showed no association between binge drinking was 8.51, so that the observed association would be unlikely before 15 weeks of gestation and risk of adverse pregnancy to disappear with unmeasured confounders. outcomes, including spontaneous preterm delivery. Third, east Asians are commonly intolerant of alcohol due to the Interpretation larger prevalence of less active or inactive forms of aldehyde Our finding of a J-shaped relationship between alcohol con- dehydrogenase-2 encoded by ALDH2*1/*2 or ALDH2*2/*2 sumption and risk of preterm delivery is consistent with the 20 3 than that found in Caucasians. Therefore, east Asians are result from the Danish pregnancy cohort study. That Dan- more likely to accumulate acetaldehyde and suffer from ish cohort study of 18 228 singleton pregnancies showed 21–23 alcohol-related diseases. However, the racial difference that ten or more drinks per week at 16 and 30 weeks of ges- in alcohol metabolism did not meet the findings from tation produced 2.9 and 3.6 times higher risks of preterm 1452 ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists Maternal alcohol consumption and preterm delivery delivery, respectively, whereas the consumption of one to Conclusion two drinks per week at 30 weeks of gestation was associated with a 31% lower risk of preterm delivery compared with In conclusion, heavy alcohol consumption in the second women who consumed less than one drink per week. and third trimesters was associated with increased risk of As for mechanisms of high alcohol consumption and risk preterm delivery among pregnant women. of preterm delivery, alcohol may induce preterm delivery through increased secretion of prostaglandins, which Disclosure of interests enhances uterine contractions. Prostaglandins also None to declare. Completed disclosure of interest forms are increase cyclic 3ʹ,5ʹ-adenosine monophosphate activity, available to view online as supporting information. which involves decreased cell division. In animal experi- ments, increased alcohol intake also induced increased sev- Contribution to authorship ere intravascular coagulation and decreased blood flow in SI, TK, AK, TS and HI contributed substantially to the concep- the placenta. According to a previous report from our tion, design, participant recruitment and data collection of the cohort, alcohol consumption (≥150 g ethanol/week) in the present study. SI and TK were involved in data analysis. SI and second and third trimesters was associated with increased HI drafted the manuscript. All authors were involved in inter- risk of hypertensive disorders of pregnancy, which is one of preting the data and critically reviewing manuscript drafts. All the risk factors for preterm delivery. authors gave approval of the final version of the manuscript. There has been no conclusive biological mechanism pro- Details of ethics approval posed for the reduced risk of preterm delivery associated The JECS was approved by the Institutional Review Board with light drinking. A previous study suggested the healthy of the Japan National Institute for Environmental Studies drinker effect in explaining the association. In the present (date of approval: 9 August 2010 and approval number: study, light drinkers during the second and third trimesters 2010-2R), as well as the Ethics Committees of all partici- had fewer hypertensive disorders. The effect of light alcohol pating institutions. consumption during pregnancy should be interpreted cau- tiously in consideration of other adverse outcomes such as Funding fetal alcohol syndrome, multiple morbidities and develop- The JECS was funded by the Ministry of the Environment, mental disorders. Japan (direct funding, no funding IDs available). We found no association between alcohol consumption in the first trimester and risk of preterm delivery. The effects of Acknowledgements different timings of alcohol consumption on the risk of pre- We are grateful to all JECS participants and all individuals term delivery remain controversial. The Danish pregnancy involved in data collection. JECS was funded by the Japa- cohort study showed singleton mothers consuming ten or nese Ministry of the Environment. The findings and con- more drinks per week at 16 weeks of gestation was associated clusions of this paper are solely the responsibility of the with increased risk of preterm delivery compared with those authors and do not represent official views of the above consuming less than one drink per week (OR 2.93, 95% CI government agency. 1.52–5.63), as with ten or more drinks per week at 30 weeks of gestation (OR 3.56, 95% CI 1.78–7.13). A case–control study of 175 singleton mothers with preterm deliveries and References 313 singleton mothers with full-term deliveries showed that 1 Albertsen K, Andersen AM, Olsen J, Grønbaek M. Alcohol 14 or more drinks per week in any trimester was associated consumption during pregnancy and the risk of preterm delivery. Am with a three-fold increase in the risk of preterm delivery J Epidemiol 2004;159:155–61. based on interviews during the postpartum hospital stay. 2 McDonald AD, Armstrong BG, Sloan M. Cigarette, alcohol, and On the other hand, a prospective study consisting of 5628 coffee consumption and prematurity. Am J Public Health 1992;82:87–90. nulliparous pregnant women (the SCOPE study) showed no 3 Kesmodel U, Olsen SF, Secher NJ. Does alcohol increase the risk of association between consuming alcohol before 15 weeks of preterm delivery? Epidemiology 2000;11:512–8. gestation with spontaneous preterm delivery or other adverse 4 Shiono PH, Klebanoff MA, Rhoads GG. Smoking and drinking during outcomes such as pre-eclampsia and infants being small for pregnancy. Their effects on preterm birth. JAMA 1986;255:82–4. their gestational age or having a low birthweight. A study 5 Lazzaroni F, Bonassi S, Magnani M, Calvi A, Repetto E, Serra F, et al. Moderate maternal drinking and outcome of pregnancy. Eur J of 3447 pregnant women in the Netherlands reported no Epidemiol 1993;9:599–606. association between alcohol consumption in each trimester 6 Lundsberg LS, Illuzzi JL, Belanger K, Triche EW, Bracken MB. Low- and the risk of preterm delivery. Further study is necessary to-moderate prenatal alcohol consumption and the risk of selected to determine the effects of alcohol consumption at different birth outcomes: a prospective cohort study. Ann Epidemiol times during pregnancy on the risk of preterm delivery. 2015;25:46–54. ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of 1453 Royal College of Obstetricians and Gynaecologists Ikehara et al. 7 Patra J, Bakker R, Irving H, Jaddoe VW, Malini S, Rehm J. Dose– 23 Chen CH, Ferreira JC, Gross ER, Mochly-Rosen D. Targeting response relationship between alcohol consumption before and aldehyde dehydrogenase 2: new therapeutic opportunities. Physiol during pregnancy and the risks of low birthweight, preterm birth Rev 2014;94:1–34. and small for gestational age (SGA) – a systematic review and meta- 24 Anton RF, Becker HC, Randall CL. Ethanol increases PGE and analyses. BJOG 2011;118:1411–21. thromboxane production in mouse pregnant uterine tissue. Life Sci 8 Aliyu MH, Lynch O, Belogolovkin V, Zoorob R, Salihu HM. Maternal 1990;46:1145–53. alcohol use and medically indicated vs. spontaneous preterm birth 25 Pennington S. Ethanol-induced growth inhibition: the role of cyclic outcomes: a population-based study. Eur J Public Health AMP-dependent protein kinase. Alcohol Clin Exp Res 1988;12:125–9. 2010;20:582–7. 26 Kennedy LA. Changes in the term mouse placenta associated with 9 Cooper DL, Petherick ES, Wright J. The association between binge maternal alcohol consumption and fetal growth deficits. Am J drinking and birth outcomes: results from the Born in Bradford Obstet Gynecol 1984;149:518–22. cohort study. J Epidemiol Community Health 2013;67:821–8. 27 Jones PJ, Leichter J, Lee M. Placental blood flow in rats fed alcohol 10 McCarthy FP, OʼKeeffe LM, Khashan AS, North RA, Poston L, before and during gestation. Life Sci 1981;29:1153–9. McCowan LM, et al. Association between maternal alcohol 28 Iwama N, Metoki H, Nishigori H, Mizuno S, Takahashi F, Tanaka K, consumption in early pregnancy and pregnancy outcomes. Obstet et al. Association between alcohol consumption during pregnancy Gynecol 2013;122:830–7. and hypertensive disorders of pregnancy in Japan: the Japan 11 Peacock JL, Bland JM, Anderson HR. Preterm delivery: effects of Environment and Children’s Study. Hypertens Res 2019;42:85–94. socioeconomic factors, psychological stress, smoking, alcohol, and 29 Berkowitz GS, Holford TR, Berkowitz RL. Effects of cigarette caffeine. BMJ 1995;311:531–5. smoking, alcohol, coffee and tea consumption on preterm delivery. 12 Verkerk PH, van Noord-Zaadstra BM, Florey CD, de Jonge GA, Early Hum Dev 1982;7:239–50. Verloove-Vanhorick SP. The effect of moderate maternal alcohol consumption on birth weight and gestational age in a low risk Appendix 1 population. Early Hum Dev 1993;32:121–9. 13 Jaddoe VW, Bakker R, Hofman A, Mackenbach JP, Moll HA, Members of JECS as of 2017 (principal investigator, Toshi- Steegers EA, et al. Moderate alcohol consumption during pregnancy hiro Kawamoto): Hirohisa Saito (National Centre for Child and the risk of low birth weight and preterm birth. The generation R study. Ann Epidemiol 2007;17:834–40. Health and Development, Tokyo, Japan), Reiko Kishi (Hok- 14 Smith LK, Draper ES, Evans TA, Field DJ, Johnson SJ, Manktelow kaido Regional Centre for JECS, Hokkaido University, Hok- BN, et al. Associations between late and moderately preterm kaido, Japan), Nobuo Yaegashi (Miyagi Regional Centre for birth and smoking, alcohol, drug use and diet: a population- JECS, Tohoku University, Sendai, Japan), Koichi Hashimoto based case–cohort study. Arch Dis Child Fetal Neonatal Ed 2015;100:F486–91. (Fukushima Regional Centre for JECS, Fukushima Medical 15 Lundsberg LS, Bracken MB, Saftlas AF. Low-to-moderate gestational University, Fukushima, Japan), Chisato Mori (Chiba Regio- alcohol use and intrauterine growth retardation, low birthweight, nal Centre for JECS, Chiba University, Chiba, Japan), Shui- and preterm delivery. Ann Epidemiol 1997;7:498–508. chi Ito (Kanagawa Regional Centre for JECS, Yokohama 16 Kawamoto T, Nitta H, Murata K, Toda E, Tsukamoto N, Hasegawa City University, Kanagawa, Japan), Zentaro Yamagata M, et al. Rationale and study design of the Japan Environment and Children’s Study (JECS). BMC Public Health 2014;14:25. (Koshin Regional Centre for JECS, University of Yamanashi, 17 Michikawa T, Nitta H, Nakayama SF, Yamazaki S, Isobe T, Tamura Yamanashi, Japan), Hidekuni Inadera (Toyama Regional K, et al. Baseline profile of participants in the Japan Environment Centre for JECS, University of Toyama, Toyama, Japan), and Children’s Study (JECS). J Epidemiol 2018;28:99–104. Michihiro Kamijima (Aichi Regional Centre for JECS, 18 Yokoyama Y, Takachi R, Ishihara J, Ishii Y, Sasazuki S, Sawada N, Nagoya City University, Aichi, Japan), Takeo Nakayama et al. Validity of short and long self-administered food frequency (Kyoto Regional Centre for JECS, Kyoto University, Kyoto, questionnaires in ranking dietary intake in middle-aged and elderly Japanese in the Japan Public Health Center-based prospective study Japan), Hiroyasu Iso (Osaka Regional Centre for JECS, for the next generation (JPHC-NEXT) protocol area. J Epidemiol Osaka University, Osaka, Japan), Masayuki Shima (Hyogo 2016;26:420–32. Regional Centre for JECS, Hyogo College of Medicine, 19 VanderWeele TJ, Ding P. Sensitivity analysis in observational research: Hyogo, Japan), Yasuaki Hirooka (Tottori Regional Centre introducing the E-Value. Ann Intern Med 2017;167:268–74. for JECS, Tottori University, Tottori, Japan), Narufumi 20 Hendershot CS, Collins SE, George WH, Wall TL, McCarthy DM, Liang T, et al. Associations of ALDH2 and ADH1B genotypes with Suganuma (Kochi Regional Centre for JECS, Kochi Univer- alcohol-related phenotypes in Asian young adults. Alcohol Clin Exp sity, Kochi, Japan), Koichi Kusuhara (Fukuoka Regional Res 2009;33:839–47. Centre for JECS, Kyushu University, Fukuoka, Japan) and 21 Ishioka K, Masaoka H, Ito H, Oze I, Ito S, Tajika M, et al. Association Takahiko Katoh (South Kyushu/Okinawa Regional Centre between ALDH2 and ADH1B polymorphisms, alcohol drinking and gastric cancer: a replication and mediation analysis. Gastric Cancer for JECS, Kumamoto University, Kumamoto, Japan). 2018;21:936–45. 22 Oze I, Matsuo K, Hosono S, Ito H, Kawase T, Watanabe M, et al. Comparison between self-reported facial flushing after alcohol consumption and ALDH2 Glu504Lys polymorphism for risk of upper aerodigestive tract cancer in a Japanese population. Cancer Sci 2010;101:1875–80. 1454 ª 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists Maternal alcohol consumption and preterm delivery Alcohol in pregnancy: not recommended at any gestational age a a,b SV Sun, TA Manuck Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Institute for Environmental Health Solutions, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Linked article: This is a mini commentary on S Ikehara et al., pp. 1448–1454 in this issue. To view this article visit https://doi.org/10.1111/1471-0528.15899 Published Online 17 September 2019. Preterm birth remains a multifactorial, caution. The stigma of alcohol con- health indicators. Lastly, even among worldwide problem. Though there are sumption in pregnancy lends itself to heavy drinkers, statistical factors substantial risk of underestimation on should also be considered, particularly multiple established risk factors for self-report. Even among alcohol drin- given the size of the cohort, as statisti- preterm birth (e.g. previous preterm kers, data were collapsed into weekly cal significance is more easily achieved. birth, short cervix), the association between maternal alcohol consump- consumption, reducing the ability to Only 0.08% (n = 73) of women in this tion and prematurity is less clear, with evaluate binge drinking versus daily cohort had moderate or heavy alcohol risk ratios ranging from 0.66 (95% CI lower levels of drinking. These data consumption in the second and third are limited to a homogeneous Japanese trimesters. Of these, just eight deliv- 0.52–0.84) to 1.34 (95% CI 1.28–1.41) population, a group more likely to ered preterm. (Strandberg-Larsen et al. Eur J Epi- have a genetic predisposition to alco- demiol 2017;32:751–64; Aliyu et al. While placing these results in the hol intolerance, which probably ‘se- Eur J Public Health 2010;20:582–7). context of current clinical recommen- lected’ for individuals who cannot dations, it is crucial to remember that Ikehara and colleagues (Ikehara tolerate alcohol, and who had an over- alcohol is an established teratogen and et al. BJOG 2019;126:1448–54) present all low rate of prematurity (4.2%). findings from the Japan Environment any degree of alcohol use during preg- Further, women with a history of and Children’s Study, a large nation- nancy can be harmful, with potential adverse pregnancy outcomes may be wide birth cohort. They reported a irreversible effects on fetal brain struc- less likely to consume substances, but ture and function and consequently on J-shaped association between the level because of their pregnancy history are short- and long-term fetal and child- of alcohol consumption in the second more likely to deliver preterm, biasing hood neurodevelopment (Williams and third trimesters and preterm the results against the abstainers. et al. Pediatrics 2015;136:e1395–406). birth; specifically, a lower risk of pre- Though women with a previous pre- maturity (adjusted odds ratio [aOR] In conclusion, these data under- term birth were excluded from analy- 0.78, 95% CI 0.60–1.00) in light drin- score the importance of screening for sis, no additional information was kers but an increased risk of prematu- alcohol consumption across gestation, provided regarding pregnancy history rity (aOR 4.52, 95% CI 1.68–12.2) in and reinforce continued recommenda- or obstetric risk factors. A sensitivity heavy drinkers (women consuming tions for abstention from alcohol dur- analysis evaluating whether the >300 g alcohol/week, ~21 standard ing pregnancy. observed effects – particularly among drinks). No relationship between first- light drinkers – persist among nulli- trimester alcohol exposure and prema- Disclosure of interests paras or those with previous uncom- turity was found. A major study Nothing to declare. Completed disclo- plicated pregnancies could address this strength is its size, as over 90 000 sure of interest forms are available to specific confounder. Additionally, pre- pregnancies were included (Ikehara view online as supporting information. maturity is used as a surrogate end et al. BJOG 2019;126:1448–54). point for the more important – albeit However, limitations abound. These Funding more difficult to study – long-term data – particularly the suggested lower outcomes of cognitive function, neu- Funded, in part, by NIH R01- rate of prematurity among light rodevelopment and other life-long MD011609 (Manuck).& drinkers – should be interpreted with ª 2019 Royal College of Obstetricians and Gynaecologists 1455

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