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.

Objective: To survey prevalence and risk factors for paternal postpartum depression symptoms at one and 6 months postpartum in Japan. Material and methods: The study participants enrolled in the prospective birth cohort study of an adjunct study of the Japan Environment & Children’s Study. Postpartum depression symptoms were evaluated using the Japanese version the Edinburgh Postnatal Depression Scale (EPDS-J). The cut-off scores on the paternal EPDS-J was eight and on maternal EPDS-J was nine, respectively. The multivariate logistic regression included an adjustment for paternal age, maternal age, the number of children in the family, family structure, paternal employment, paternal academic history, household income, paternal smoking status, paternal history of mental health disorders, the Kessler 6-item psychological distress scale (K6) score during pregnancy, infertility treatment, paternal mental intimate partner violence (IPV) during pregnancy, paternal physical IPV during pregnancy, the sex of the newborn, congenital anomalies of the newborn, infant disease under medical treatment, returning to the maternal parent’s house to give birth or take care of infant, the father’s history of disease or injury that required medical treatment, paternity leave, and the EPDS-J for mothers. Results: A total of 1023 and 1330 fathers and their spouse who had a single delivery were assessed at one and 6 months postpartum, respectively. The prevalence of paternal EPDS-J scores ≥ 8 was 11.2 and 12.0% at one and 6 months postpartum, respectively. In the multiple logistics analysis, paternal EPDS-J scores ≥ 8 at 1 month postpartum was significantly associated with history of mental health disorders (adjusted odds ratio (AOR) 2.825; 95% confidence interval (CI): 1.047–7.623), K6 score ≥ 13 during pregnancy (AOR 4.116; 95% CI: 1.598–10.599), household income < 4 × 10³ yen (AOR 1.799; 95% CI: 1.072–3.021), and infant disease under medical treatment (AOR 1.720; 95% CI: 1.015–2.915). Paternal EPDS-J scores ≥ 8 at 6 months postpartum was significantly associated with K6 scores ≥ 13 during pregnancy (AOR 4.621; 95% CI: 2.113–10.107), unemployment (AOR 3.751; 95% CI: 1.739–8.091) and maternal EPDS-J scores ≥ 9 (AOR 4.621; 95% CI: 2.113–10.107). Conclusion: The prevalence of paternal postpartum depression symptoms were 11.2 and 12.0% at one and 6 months postpartum. Paternal postpartum depression symptoms at 1 month postpartum was associated with history of mental health disorders, psychological distress during pregnancy, low income, and infant disease under medical treatment. Paternal postpartum depression symptoms at 6 months postpartum was associated with psychological distress during pregnancy, unemployment, and maternal postpartum depression. It is important to consider the paternal postpartum depression symptoms, and further enlightenment regarding these issues is recommended in Japan.

Objective: To survey the frequency and risk factors for father-to-infant lack of affection (LA) and anger / rejection (AR) bonding failure at 1 month postpartum. Material and methods: The study participants enrolled in the prospective birth cohort study of an adjunct study of the Japan Environment & Children’s Study. Bonding failure, psychological distress during pregnancy and postnatal depression symptoms were evaluated using the Japanese version of the Mother-Infant Bonding Scale (MIBS-J), the Kessler 6-item (K6) psychological distress scale and the Edinburgh Postnatal Depression Scale (EPDS-J). This study extracted relative factors based on approximately 10% occupancy of the total high scores in MIBS-J subscales as a cut-off for bonding failure. The cut-off scores on the paternal EPDS-J was eight, on maternal EPDS-J was nine, and on the K6 psychological distress scale score was thirteen. Results: A total of 1008 couples who had single delivery were assessed at 1 month postpartum, respectively. The prevalence of paternal MIBS-J_LA scores ≥ 4 was 8.3%, MIBS-J_AR scores ≥ 3 was 7.9%, and EPDS-J scores ≥ 8 was 11.2%, respectively. In the multiple logistics analysis, paternal MIBS-J_LA scores ≥ 4 were significantly associated with maternal MIBS-J_LA score ≥ 3 (adjusted odds ratio (AOR) 2.814; 95% confidence interval (CI): 1.377–5.747), mental intimate partner violence (IPV) against the mother during pregnancy (AOR 2.176; 95% CI: 1.185–3.997), maternal K6 psychological distress scale score ≥ 13 (AOR 2.980; 95% CI: 1.317–6.745), paternal EPDS-J score ≥ 8 (AOR 3.227; 95% CI: 1.767–5.892), and a history of mental health disorder (AOR 4.125; 95% CI: 1.423–11.963). Paternal MIBS-J_AR scores ≥ 3 were significantly associated with maternal MIBS-J_AR scores ≥ 3 (AOR 5.082; 95% CI: 2.453–10.529), a history of physical IPV against the mother during pregnancy (AOR 5.230; 95% CI: 1.016–26.920), paternal K6 psychological distress scale score ≥ 13 (AOR 4.145; 95% CI: 1.311–13.107), and paternal EPDS-J scores ≥ 8 (AOR 4.479; 95% CI: 2.503–8.013). In the Pearson’s product moment correlation coefficient analyses between paternal and maternal MIBS-J score; MIBS-J_LA scores was r = 0.2112 p < 0.0001, and MIBS-J_AR scores was r = 0.3281 p < 0.0001. Conclusion: Father-to-infant lack of affection bonding failure was associated with mother-to-infant lack of affection bonding failure, mental IPV against mother during pregnancy, maternal psychological distress during pregnancy, paternal postpartum depression symptoms and history of paternal mental health disorders. Father-to-infant anger / rejection bonding failure was associated with mother-to-infant anger / rejection bonding failure, physical IPV against mother during pregnancy, paternal psychological distress during pregnancy, and paternal postpartum depression symptoms. Since bonding failure is a risk factor for infant maltreatment, further investigations are recommended to fully assess these associations to resolve parent perinatal mental health issues for preventing father-to-infant bonding failure.

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.

We aimed to examine the impact of a preconception pro-inflammatory diet on gestational diabetes mellitus (GDM) using singleton pregnancy data from the Japan Environment and Children’s Study involving live births from 2011 to 2014. Individual meal patterns before pregnancy were used to calculate the dietary inflammatory index (DII). Participants were categorized according to DII quartiles 1–4 (Q1 and Q4 had the most pro-inflammatory and anti-inflammatory diets, respectively). The participants were stratified into five groups by pre-pregnancy body mass index (BMI): G1 to G5 (<18.5 kg/m², 18.5 to <20.0 kg/m², 20.0 to <23.0 kg/m², 23.0 to <25.0 kg/m², and ≥25.0 kg/m², respectively). A multiple logistic regression model was used to estimate the effect of the anti-inflammatory diet on GDM, early diagnosed (Ed)-GDM, and late diagnosed (Ld)-GDM in each BMI group. Trend analysis showed that the risk of GDM, Ed-GDM, and Ld-GDM increased with increased pre-pregnancy BMI values. In the G4 group, the risk of Ed-GDM increased in Q2 and Q4. This study suggests that, although higher maternal BMI increases the risk of GDM, the effect of a preconception pro-inflammatory diet on the occurrence of GDM depends on pre-pregnancy BMI. This result may facilitate personalized preconception counseling based on maternal BMI.