Purpose: To elucidate drug use before and during pregnancy in Japan. Methods: The Japan Environment and Children’s Study (JECS) is an ongoing nationwide birth cohort study. We analyzed data from JECS involving cases where drugs were used for 12 months before pregnancy was diagnosed, between the time of diagnosis of pregnancy until week 12 of pregnancy, and after week 12 of pregnancy. Results: We analyzed data from 97,464 pregnant women. The percentages of pregnant women who had taken one or more drugs and supplements before diagnosis of pregnancy, between the time of diagnosis of pregnancy until week 12 of pregnancy, and after week 12 of pregnancy, were 78.4%, 57.1%, and 68.8% respectively. Excluding iron supplements, folic acid, and other vitamins and minerals, the percentages of women taking supplements were 75.3%, 36.0%, and 51.7% at each respective time point. The following drugs and supplements were frequently used for 12 months before pregnancy diagnosis: Commercially available antipyretics, analgesics, and/or medicine for treating common cold (34.7%), antipyretics, analgesics, and/or medicine for treating common colds, which were prescribed in hospitals (29.8%), antimicrobial drugs (14.0%), and anti-allergy drugs (12.5%). The following drugs and supplements were frequently used from the time of pregnancy diagnosis until week 12 of pregnancy, and after week 12 of pregnancy: folic acid (28.9% and 26.2%), antipyretics, analgesics and/or medicines for treating common cold, that were prescribed in hospitals (7.8% and 13.3%), Chinese herbal medicines (6.0% and 9.4%, and uterine relaxants (5.1% and 15.2%). Conclusions: The analysis of a nationwide cohort study showed that a high percentage of Japanese pregnant women were taking medicinal drugs. Further research is required to elucidate the relationship between drug use during pregnancy and birth defects in Japan.

Involvement of family members, especially grandparents, in genome epidemiological research is important to investigate both genetic and environmental factors of common diseases. The aim of the present study was to establish strategies to obtain enough number of family recruitment, especially focusing on grandparents, for the Tohoku Medical Megabank Birth and Three-Generation Cohort Study. Our main strategies are summarized below. 1) We standardized informed consent process with reference materials to help people understand the consent form, 2) we created an invitation letter to contact family members, and 3) we recruited family members in several settings. To obtain informed consent, we were careful of explaining clearly the complex reasons as well as drawing people’s attention. By the end of March 2017, the number of invitation letters distributed to family members through the pregnant women was 23,806, including 18,702 grandparents. Among the grandparents who received invitation letters, 2,935 (15.7%) responded to us. Furthermore, some grandparents were asked to provide informed consent with other family members by staff at maternal clinics or Community Support Centers, and others directly booked Community Support Centers without responding to the invitation letter. Grandparents joined the study anytime during mother’s maternal check-ups or delivery. Overall, 8,054 grandparents participated in our birth cohort study. The setting in which most grandparents were recruited was our own facilities. Importantly, both paternal and maternal grandparents more frequently participated in the study if the father also participated. In conclusion, we are able to recruit not only pregnant women but also fathers and grandparents.

Background: Recent literature suggest the effect of maternal smoking on risk of hypertensive disorders in pregnancy (HDP) and preeclampsia may differ by ethnicity, however studies on Asians are limited.Methods: We investigated the association between maternal smoking and HDP and preeclampsia, by using a common analysis protocol to analyze the association in six birth cohorts participating in a Japanese consortium of birth cohorts (JBiCC). Results were compared with published results from cohorts not included in this consortium, and where possible produced a meta-analysis including these studies.Results: Meta-analysis of four cohort studies including 28,219 participants produced an odds ratio (OR) of 1.24 (95% confidence interval (CI) 0.88-1.87) for effect of smoking beyond early pregnancy compared to women who did not smoke during pregnancy. These results combined with those from the Japan Environment and Children’s Study (JECS) yielded an OR of 1.19 (95%CI 1.00-1.43, p=0.056). Meta-analysis results for categories of smoking volume were insignificant, but when combined with JECS yielded an OR of 0.86 (95%CI 0.65-1.12) for smoking 1-4 cigarettes, 1.25 (95%CI 0.98-1.60) for smoking 5-9 cigarettes, and 1.27 (95%CI 1.04-1.54) for smoking 10 or more cigarettes per day. All effects were insignificant for preeclampsia.Conclusion: Our results suggest the protective effect of smoking longer, smoking more on HDP and preeclampsia repeatedly observed among Europeans and North Americans likely do not hold for the Japanese.

Some studies have suggested that blastocyst transfer is associated with i) imbalance in the secondary sex ratio (SSR) (which favors male offspring), ii) increased incidence of monozygotic twins (MZT). In contrast, others have not found these changes. In this study, we evaluated the association between blastocyst transfer and SSR and MZT, considering potential parental confounders. The Japan Environment and Children’s Study is a large, nationwide longitudinal birth cohort study funded by the Ministry of the Environment of Japan. We used this large dataset, including 103,099 pregnancies, to further investigate the association between blastocyst transfer, SSR and MZT, using spontaneously conceived pregnancies, non-assisted reproductive technology (non-ART) treatment (intrauterine insemination and ovulation induction with timed intercourse) and cleavage stage embryo transfer for comparison. We evaluated the association with each group, the SSR, and the frequency of MZT, calculating the adjusted odds ratio (AOR) using multivariable logistic regression analyses, adjusting for potential parental confounders such as basic health and socioeconomic status. For each group (spontaneous conception vs. non-ART treatment vs. cleavage stage embryo transfer vs. blastocyst transfer), the percentages of males were 51.3% vs 50.7% vs 48.9% vs 53.4% and the monozygotic twinning rates per pregnancy were 0.27% vs 0.11% vs 0.27% vs 0.99% respectively. Multivariate logistic regression analyses indicated that blastocyst transfer was significantly associated with a higher SSR and higher incidence of MZT than the other three groups (SSR: AOR 1.095, 95% CI1.001–1.198; MZT: AOR 4.229, 95% CI 2.614–6.684). There are significant relationships between blastocyst transfer and SSR imbalance and a higher occurrence of MZT.