Maternal birth weight is an indicator of preterm delivery: the Japan environment and children's study.

This study aimed to investigate the association between maternal birth weight (MBW) with preterm delivery (PTD) in the Japanese population. To this end, a total of 78,972 Japanese pregnant women were included in a prospective birth cohort study. Multiple logistic regression and multinominal logistic regression models were applied to investigate the associations of MBW with PTD (delivery from 22 to < 37 weeks of gestation), early PTD (delivery from 22 to < 34 weeks), and late PTD (delivery from 34 to < 37 weeks). The results showed that MBW was inversely associated with PTD, early PTD, and late PTD (p-for-trend < 0.0001, 0.0014, and < 0.0001, respectively). The adjusted odds ratios per each 500 g of MBW decrease were 1.167 (95% confidence interval [CI]: 1.118-1.218) for PTD, 1.174 (95% CI: 1.070-1.287) for early PTD and 1.151 (95% CI: 1.098-1.206) for late PTD. The effect size of the association of MBW with early PTD was similar to that with late PTD. This study demonstrated for the first time an association of a low MBW with PTD, early PTD, and late PTD in a Japanese nationwide cohort.

Maternal birth weight as an indicator of early-onset and late-onset hypertensive disorders of pregnancy: The Japan Environment and Children's study.

OBJECTIVES: This study aimed to investigate the association between maternal birth weight (MBW) and hypertensive disorders of pregnancy (HDP) according to the gestational age when HDP develops. STUDY DESIGN: A total of 77,345 subjects were included in this prospective birth cohort study. The association between MBW and HDP was investigated by a multinomial logistic regression model. MAIN OUTCOME MEASURES: Early-onset HDP (EO-HDP), preterm late-onset HDP (preterm LO-HDP), and term late-onset HDP (term LO-HDP). RESULTS: Lower MBW was associated with higher odds of preterm and term LO-HDP (p-values for trend < 0.0001 and = 0.0005, respectively). A linear association between MBW and EO-HDP was observed (p-values for trend = 0.0496). The shape of the association between MBW and preterm LO-HDP was a combination of the associations between MBW with EO-HDP or LO-HDP. The effect size of the association between MBW < 2,500 g and EO-HDP was lower than that of MBW < 2,500 g with preterm or term LO-HDP. The adjusted odds ratios for EO-HDP, preterm LO-HDP, and term LO-HDP in subjects with MBW < 2,500 g were 1.052 (95 % confidence interval [CI]: 0.665-1.664), 1.745 (95 % CI: 1.220-2.496), and 1.496 (95 % CI: 1.154-1.939), respectively. CONCLUSIONS: MBW was associated with HDP, regardless of gestational age when HDP developed. Furthermore, the association of MBW < 2,500 g with preterm or term LO-HDP was stronger than that with EO-HDP.

Factors associated with postpartum smoking relapse at early postpartum period of Japanese women in the Japan Environmental and Children's Study.

BACKGROUND: Postpartum smoking relapse is a serious public health concern. Previous studies have identified several risk factors for postpartum smoking relapse; however, very little is known about the predictors of early postpartum smoking relapse. This study aimed to determine postpartum smoking relapse status and its associated risk factors at 1 month postpartum among Japanese women. METHODS: Data were obtained from 93,851 mothers with live births in an ongoing birth cohort study, the Japan Environment and Children's Study. Data on smoking status and confounding variables were collected using self-administered questionnaires and medical record transcripts. Self-administered questionnaires were administered during the first trimester, second/third trimester, and 1 month after delivery. A multiple logistic regression analysis was performed. RESULTS: Among the 14,326 mothers who smoked during pregnancy, 10,917 (76.2%) quit smoking during pregnancy. Subsequently, 617 (5.7%) of the mothers who had quit relapsed smoking at 1 month postpartum. Maternal age (≤24, ≥35), maternal education (≤12 years), parity (≥Second), feeding method (Formula milk), partner smoking status during pregnancy (Smoker), number of cigarettes per day before the cessation of smoking (≥11), maternal alcohol consumption at 1-month postpartum (Drinker), postpartum depression (EPDS score ≥9), and spending time at the parents' home after delivery (≥14 days) were associated with smoking relapse. CONCLUSIONS: A certain number of mothers relapsed even 1 month postpartum. Besides mother's alcohol and smoking habit before pregnancy, breastfeeding and partner smoking are important factors in early postpartum smoking relapse in Japan.

Factors associated with new onset of father-to-infant bonding failure from 1 to 6 months postpartum: an adjunct study of the Japan environment and children's study.

PURPOSE: This study aimed to determine the factors associated with new onset father-to-infant (paternal) bonding failure from 1 to 6 months postpartum. METHODS: This was a prospective birth-cohort study. Paternal bonding failure was evaluated using the Japanese version of the Mother-to-Infant Bonding Scale (MIBS-J) at 1 and 6 months postpartum. For cut-off scores, overall bonding failure, MIBS-J total scores ≥ 5; subscale for lack of affection, MIBS-J_LA scores ≥ 3; and subscale for anger/rejection, MIBS-J_AR scores ≥ 3 were used in this study. Multivariate regression analysis was performed to analyze relative variables. RESULTS: We analyzed 872 fathers. The frequency of new-onset overall bonding failure, lack of affection, and anger/rejection was 5.6%, 4.9%, and 6.3%, respectively. For new-onset overall bonding failure, significant associated factors were paternal childcare leave (adjusted odds ratio [AOR] 3.192; 95% confidence interval [CI] 1.203-8.469), paternal new-onset depression symptoms (AOR 3.181; 95% Cl 1.311-7.716), and maternal new-onset overall bonding failure (AOR 4.595; 95% Cl 1.119-18.866). For new-onset lack of affection, significant associated factors were preterm birth (AOR 4.189; 95% Cl 1.473-11.913) and paternal new-onset depression symptoms (AOR 3.290; 95% Cl 1.294-8.362). For new-onset anger and rejection, significant associated factors were paternal childcare leave (AOR 3.142; 95% Cl 1.138-8.676), paternal new-onset depression symptoms (AOR 2.829; 95% Cl 1.133-7.068), and maternal new-onset anger/rejection (AOR 7.064; 95% Cl 2.300-21.700). CONCLUSIONS: The factors associated with new-onset paternal bonding failure from 1 to 6 months postpartum were paternal childcare leave, preterm birth, paternal postpartum depression symptoms, and maternal bonding failure.

Secondhand smoke exposure is associated with the risk of hypertensive disorders of pregnancy: the Japan Environment and Children's Study.

Hypertensive disorders of pregnancy (HDP) are associated with poor maternal and neonatal prognoses. Although several studies have indicated an effect of secondhand smoke (SHS) exposure on HDP, such evidence is lacking in Japan. Therefore, we analyzed data from the Japan Environment and Children's Study, a large-scale epidemiological investigation, to elucidate a possible link between SHS exposure and HDP risk. Data were obtained from the all-birth fixed datasets and included information on 104,062 fetuses and their parents. SHS exposure was assessed in terms of the frequency (rarely, 1-3, or 4-7 days/week) and the daily duration of exposure (<1, 1-2, or ≥2 h(s)/day). Modified Poisson regression model analyses were performed with adjustment for known risk factors for HDP. Additionally, the population attributable fractions (PAFs) of SHS exposure and maternal smoking to HDP prevalence were estimated. The relative risks of developing HDP among individuals with SHS exposures of 4-7 days/week and ≥2 h/day were 1.18 and 1.27 (95% confidence interval: 1.02-1.36 and 0.96-1.67), respectively, compared to the reference groups (rare exposure and <1 h/day). The PAFs for the risk of HDP due to SHS exposure and perinatal smoking were 3.8% and 1.8%, respectively. Japanese women with greater exposure to SHS have a higher risk of HDP after adjustment for possible confounding factors; thus, relevant measures are required to reduce SHS exposure to alleviate HDP risk. The association between second-hand smoking exposure and hypertensive disorders of pregnancy risk was analyzed using the JECS data. The relative risks in 4-7 days/week and ≥2 h/day of SHS exposures were 1.18 and 1.27, respectively. The PAFs due to SHS exposure and maternal smoking were 3.80% and 1.81%, respectively.

Social Capital and Physical Activity among Japanese Pregnant Women: Adjunct Study of Japan Environment and Children's Study in Miyagi Prefecture.

Adequate physical activity during pregnancy is crucial for maternal and fetal health. Although physical activity during pregnancy is restricted, social support and trust may have a favorable influence on physical activity. This study aimed to examine the association between cognitive social capital during pregnancy and prenatal physical activity among Japanese individuals. We also investigated whether social capital has an extended influence during pregnancy on physical activity 1.5 years after delivery. The cognitive social capital of 3,055 pregnant women in their second trimester was measured using nine questions on a self-administered questionnaire. Each cognitive social capital was classified into two or four groups based on their scores. Physical activity during pregnancy was measured using a validated questionnaire in the second trimester and at 1.5 years after delivery. Participants were classified as having adequate physical activity (≥ 150 min/week) or inadequate physical activity (< 150 min/week) based on the physical activity guidelines during pregnancy. After adjusting for confounders, emotional support was positively associated with the prevalence of adequate prenatal physical activity (P for trend = 0.002). Moreover, there was a positive association between emotional support during pregnancy and the prevalence of adequate physical activity 1.5 years after delivery. Among Japanese women, emotional support during pregnancy was associated with a higher prevalence of adequate prenatal physical activity during pregnancy and at 1.5 years after delivery.

Timing of Maternal Smoking Cessation and Newborn Weight, Height, and Head Circumference.

OBJECTIVE: To examine the relationship between timing of smoking cessation during pregnancy and anthropometric indices of newborns. METHODS: Mothers and neonates enrolled in the JECS (Japan Environment and Children's Study), a nationwide birth cohort study, were examined. Patients with full-term neonates were included in the analysis, and 73,025 mother-neonate pairs with complete data were identified. The mothers were classified into six groups according to smoking status during pregnancy (nonsmokers [Q1, n=44,198]; ex-smokers who quit before pregnancy [Q2, n=16,461]; ex-smokers who quit in the first trimester [Q3, n=8,948]; ex-smokers who quit in the second trimester [Q4, n=498]; ex-smokers who quit in the third trimester [Q5, n=651]; and smokers who smoked throughout pregnancy [Q6, n=2,269)]). Data on smoking were based on questionnaires administered in the first, second, or third trimester and 1 month after delivery. The primary outcomes were birth weight, height, and head circumference. RESULTS: Compared with nonsmokers (Q1), no adverse outcomes were observed for ex-smokers who quit before pregnancy (Q2). The mean adjusted weights of male and female neonates were 135 g and 125 g lower, respectively, in Q6 participants than in Q1 participants. Comparing Q1 and Q6 participants, height was 0.6 cm and 0.7 cm smaller for male and female neonates, respectively. Head circumference in neonates of Q6 participants was 0.3 cm and 0.3 cm smaller for male and female neonates, respectively, than that in Q1 participants. Across all three measures, smoking cessation in the first and second trimester reduced the differential in outcomes between nonsmokers and individuals who smoked throughout pregnancy. CONCLUSION: Smoking during pregnancy is associated with reduced newborn birth weight, height, and head circumference. Earlier smoking cessation during pregnancy reduces the adverse effects of smoking on fetal growth.

The impact of maternal and paternal birth weights on infant birth weights: the Japan environment and children's study.

This study aimed to evaluate the association between parental and infant birth weights in Japan. In total, 37,504 pregnant Japanese women and their partners were included in this birth cohort study. A multinomial logistic regression model was used to evaluate the associations of parental birth weights with small-for-gestational-age (SGA) or large-for-gestational-age (LGA) infants. Associations between parental birth weight and low birth weight (LBW) infants or macrosomia were also examined, and linear associations between parental birth weight and SGA or LGA were found. The adjusted odds ratios (aORs) for SGA infants per 500 g decrease in maternal and paternal birth weights were 1.50 (95% confidence interval [CI],1.43-1.58) and 1.31 (95% CI, 1.25-1.38), respectively. The aORs for LGA infants per 500 g increase in maternal and paternal birth weights were 1.53 (95% CI, 1.47-1.60) and 1.41 (95% CI, 1.35-1.47), respectively. The association between parental birth weight and LBW infants or macrosomia was also linear. The aORs for LBW infants per 500 g decrease in maternal and paternal birth weights were 1.47 (95% CI, 1.40-1.55) and 1.25 (95% CI, 1.19-1.31), respectively. The aORs for macrosomia per 500 g increase in maternal and paternal birth weights were 1.59 (95% CI, 1.41-1.79) and 1.40 (95% CI, 1.23-1.60), respectively. Parental birth weight was found to be associated with infant birth weight even after adjusting for various parental factors. Furthermore, maternal birth weight was more strongly associated with infant birth weight than with paternal birth weight.

Association of fish intake with menstrual pain: A cross-sectional study of the Japan Environment and Children's Study.

The relationship between fish eating habits and menstrual pain is unknown. Elucidating this relationship can inform dietary guidance for reproductive age women with menstrual pain. The aim of this study was to clarify the relationship between fish intake frequency/preference and menstrual pain. This cross-sectional study was conducted at the Miyagi Regional Center as an adjunct study of the Japan Environment and Children's Study, and 2060 eligible women (mean age, 31.9 years) participated. Fish intake frequency ("< 1 time/week," "1 time/week," "2-3 times/week," or "≥ 4 times/week"), preference ("like," "neutral," or "dislike"), and menstrual pain (no/mild or moderate-to-severe) were assessed at 1.5 years after the last delivery through self-administered questionnaires. The association between fish intake frequency/preference and prevalence of moderate-to-severe menstrual pain was evaluated through logistic regression analyses. Our results show that, compared with the "< 1 time/week" (38.0%) group, the "1 time/week" (26.9%), "2-3 times/week" (27.8%), and "≥ 4 times/week" (23.9%) groups showed a lower prevalence of moderate-to-severe menstrual pain (p < 0.01). The prevalence of moderate-to-severe menstrual pain was 27.7%, 27.6%, and 34.4% in the "like," "neutral," and "dislike" groups, respectively. Multivariate logistic regression showed that frequent fish intake was associated with a lower prevalence of moderate-to-severe menstrual pain ("1 time/week": odds ratio [OR] = 0.59; 95% confidence interval [CI], 0.41-0.86, "2-3 times/week": OR = 0.64; 95% CI, 0.45-0.90 and "≥ 4 times/week": OR = 0.52; 95% CI, 0.34-0.80; trend p = 0.004). Multivariate logistic regression showed no association between fish preference and moderate-to-severe menstrual pain ("dislike" vs "like": OR = 1.16; 95% CI, 0.78-1.73). There was a significant negative association between fish intake frequency and menstrual pain. It is suggested that fish intake can reduce or prevent menstrual pain.

Association between whole blood metallic elements concentrations and gestational diabetes mellitus in Japanese women: The Japan environment and Children's study.

BACKGROUND: Exposure to several metallic elements has been suggested as a risk factor for gestational diabetes mellitus (GDM), but inconsistent findings have been reported. This study aimed to examine the association between the maternal whole blood concentration of metallic elements (Hg, Pb, Cd, Mn, and Se) and GDM using the dataset of the Japan Environment and Children's Study (JECS), a nationwide birth cohort study, which was designed to examine the adverse effects of pre/post-natal exposure to hazardous environment. METHODS: The data of 78,964 pregnant women who were participants of JECS were used. Blood samples were collected from the pregnant women at second/third trimester of gestation. We employed logistic regression analysis, quantile g-computation (QGC) and a distributed lag nonlinear model (DLNM) to examine the association between the blood concentration of metallic elements and the risk of GDM. RESULTS: The prevalence of GDM was 2.1%. In the logistic regression analyses, maternal blood Hg was associated with an increased risk of GDM. In QGC analysis, although metallic elements mixtures were not related to an increased risk of GDM, Hg (52.6%) may be the main contributor. According to the results of DLNM, for maternal exposure to Hg, 4.99 ng/g was identified as its susceptible minimum window for elevated risk of GDM. CONCLUSIONS: Our findings highlighted an association between Hg exposure and an increased risk of GDM. Studies of the underlying mechanisms and potential contributing factors, including fish intake, of this association are warranted.

Prenatal folic acid supplementation and autism spectrum disorder in 3-year-old offspring: the Japan environment and children's study.

OBJECTIVE: We evaluated the relationship between prenatal folic acid supplementation and autism spectrum disorder (ASD) in 3-year-old offspring. METHODS: We used data from the Japan Environment and Children's Study, a nationwide prospective birth cohort study. We analyzed the data to determine the association between folic acid supplement use and the incidence of ASD in offspring, and classified participants into three groups based on the time of initiation of folic acid supplementation, as follows: (1) preconception users of folic acid supplements and (2) post-conception users, and (3) non-users. The dietary folate intake of study participants was also classified into three groups (<200 µg, 200 µg to <400 µg, ≥400 µg). RESULTS: Overall, 361 offspring of 96,931 participants with single pregnancies were diagnosed with ASD (0.37%). A total of 7,046 participants (7.3%) used folic acid supplements before conception, 29,984 (30.9%) took them after detection of pregnancy, and 59,901 (61.8%) never received them. Multivariate logistic regression analyses demonstrated no association between prenatal folic acid supplementation and ASD in offspring (preconception use: adjusted odds ratio [AOR], 1.189; 95% confidence interval [CI], 0.819-1.727 and post-conception use: AOR, 1.072; 95% CI, 0.840-1.368); additionally, no association was observed with the use of folic acid supplements and/or multivitamin supplements (preconception use: AOR, 1.273; 95% CI, 0.921-1.760 and post-conception use: AOR, 1.132; 95% CI, 0.885-1.449). Moreover, no significant association was observed in participants with combined prenatal supplement use and dietary folate intake. CONCLUSIONS: Maternal use of folic acid supplements from the pre- or post-conception period was not significantly associated with ASD in 3-year-old offspring in Japan. Evaluation of the dietary folate intake from preconception also showed no significant association.

The prevalence of psychological distress during pregnancy in Miyagi Prefecture for 3 years after the Great Eas t Japan Earthquake.

BACKGROUND: To examine changes in psychological distress prevalence among pregnant women in Miyagi Prefecture, which was directly affected by the Great East Japan Earthquake and tsunami, and compare it with the other, less damaged areas of Japan. METHODS: This study was conducted in conjunction with the Japan Environment and Children`s Study. We examined 76,152 pregnant women including 8270 in Miyagi Regional Center and 67,882 in 13 other regional centers from the all-birth fixed data of the Japan Environment and Children's Study. We then compared the prevalence and risk of distress in women in Miyagi Regional Center and women in the 13 regional centers for 3 years after the disaster. RESULTS: Women in the Miyagi Regional Center suffered more psychological distress than those in the 13 regional centers: OR 1.38 (95% CI, 1.03-1.87) to 1.92 (95% CI, 1.42-2.60). Additionally, women in the inland area had a consistently higher prevalence of psychological distress compared to those from the 13 regional centers: OR 1.67 (95% CI, 1.18-2.38) to 2.19 (95% CI, 1.60-2.99). CONCLUSIONS: The lack of pre-disaster data in the Japan Environment and Children's Study made it impossible to compare the incidence of psychological distress before and after the March 2011 Great East Japan Earthquake. However, 3 years after the Great East Japan Earthquake, the prevalence of pregnant women with psychological distress did not improve in Miyagi Regional Center. Further, the prevalence of mental illness in inland areas was consistently higher than that in the 13 regional centers after the disaster.

Interannual Changes in the Prevalence of Intimate Partner Violence Against Pregnant Women in Miyagi Prefecture After the Great East Japan Earthquake: The Japan Environment and Children's Study.

This study aimed to clarify the interannual changes in intimate partner violence against pregnant women after the March 11, 2011 Great East Japan Earthquake in target areas of Miyagi Prefecture that were damaged by the earthquake and tsunami. Because of this disaster, in Miyagi Prefecture, approximately 12,000 people died or went missing, and approximately 238,000 buildings were destroyed. According to the U.S. Geological Survey, the Great East Japan Earthquake is the fourth largest earthquake in the world and the largest in Japan since 1900. The present study was part of the Japan Environment and Children's Study. Data from June 2011 to May 2014 of 79,222 pregnant women were analyzed, calculating the prevalence of physical and mental intimate partner violence in the inland, north coastal, and south coastal areas of Miyagi. These prevalence rates were compared with nationwide rates of intimate partner violence in 2011 using univariate and logistic regression analyses. After the disaster, the incidence of mental intimate partner violence increased in the south coastal area and then improved later (19.4%, 13.1%, and 13.3% for south coastal area, and 13.8%, 13.8%, and 13.1% for nationwide in 2011, 2012, and 2013, respectively). However, in the north coastal area, the incidence of physical intimate partner violence increased after the disaster and then improved later (2.7%, 1.5%, and 1.3% for north coastal area, and 1.4%, 1.3%, and 1.1% for nationwide in 2011, 2012, and 2013, respectively). In the inland area, however, the prevalence of both mental and physical intimate partner violence was consistently higher than nationwide rates after the disaster.

Associations between glycosylated hemoglobin level at less than 24 weeks of gestation and adverse pregnancy outcomes in Japan: The Japan Environment and Children's Study (JECS).

AIMS: To investigate the associations between glycosylated hemoglobin (HbA1c) levels at less than 24 weeks of gestation and adverse pregnancy outcomes in Japan. METHODS: This was a prospective nationwide birth cohort study of 77,526 subjects with an HbA1c level of <6.5% (<48 mmol/mol) at less than 24 weeks of gestation. Associations of HbA1c level with adverse pregnancy outcomes were evaluated using multivariate analyses. RESULTS: The adjusted odds ratios per 1% (11 mmol/mol) increase in HbA1c level were 1.77 (95% confidence interval [CI]: 1.48-2.12) for hypertensive disorders of pregnancy; 1.78 (95% CI: 1.12-2.83) for placental abruption; 1.30 (95% CI: 1.12-1.50) for preterm birth; 2.11 (95% CI: 1.41-3.16) for very preterm birth; 1.49 (95% CI: 1.33-1.68) for low birth weight infants; 1.95 (95% CI: 1.42-2.70) for macrosomia; 1.23 (95% CI: 1.09-1.39) for small for gestational age; 1.15 (95% CI: 1.04-1.28) for large for gestational age; and 1.29 (95% CI: 1.20-1.39) for the composite adverse pregnancy outcome. CONCLUSIONS: The higher the HbA1c level, the higher the risk of adverse pregnancy outcomes in Japan. Further studies will be needed to determine prenatal management based on the HbA1c level in pregnant women with HbA1c <6.5% (<48 mmol/mol) at less than 24 weeks of gestation.

Update on the prevalence and determinants of folic acid use in Japan evaluated with 91,538 pregnant women: the Japan Environment and Children's Study.

Objective: To provide the latest and most promising evidence on the prevalence and determinants for folic acid supplementation in pregnant women in Japan, including differences in prevalence between interview years and determinants across regions.Materials and methods: The study participants were enrolled from 15 regional centers across Japan between January 2011 and March 2014. Information on the use of folic acid supplementation before and during pregnancy and the characteristics of the participants were collected using questionnaires, medical chart reviews, and interviews by research coordinators.Results: Data for 91,538 women who provided sufficient data on folic acid supplementation were analyzed. The prevalence of adequate users was 8.0%, which, although low, tended to improve over the 4-year recruitment period. Various kinds of sociodemographic factors, lifestyle habits, and obstetrical and medication use history were significant and independent determinants for folic acid use. Associations between adequate preconception folic acid use and its major determinants tended to be similar across regions.Conclusions: Although the prevalence of adequate folic acid use was low, it increased from 2011 to 2014. Reproductive-aged women who have determinants for inadequate folic acid use should be informed about the need for preconception folic acid supplementation to help prevent neural tube defects.

Mother-to-infant bonding failure and intimate partner violence during pregnancy as risk factors for father-to-infant bonding failure at 1 month postpartum: an adjunct study of the Japan Environment and Children's Study.

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 were eight, on maternal EPDS-J was 9, and on the K6 psychological distress scale score was 13.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 Pearson's product moment correlation coefficient analyses between paternal and maternal MIBS-J score, MIBS-J_LA score was r = 0.2112, p < .0001, and MIBS-J_AR score was r = 0.3281, p < .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.

The prevalence and risk factors for postpartum depression symptoms of fathers at one and 6 months postpartum: an adjunct study of the Japan Environment & Children's Study.

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 and Children's Study. Postpartum depression symptoms were evaluated using the Japanese version of the Edinburgh Postnatal Depression Scale (EPDS-J). The cut-off scores on the paternal EPDS-J were 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 <4000 × 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 2.460; 95% CI: 1.514-3.996).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 were associated with the 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 were 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.

The risk of secondary sex ratio imbalance and increased monozygotic twinning after blastocyst transfer: data from the Japan Environment and Children's Study.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: There are significant relationships between blastocyst transfer and SSR imbalance and a higher occurrence of MZT.

Higher prevalence of hypertensive disorders of pregnancy in women who smoke: the Japan environment and children's study.

Smoking during pregnancy is a risk factor for various adverse birth outcomes but lowers the risk of preeclampsia. Cardiovascular adaptations might underlie these associations. We examined the association of maternal smoking with the risk of hypertensive disorders of pregnancy (HDP) in a low-risk population-based cohort of 76,303 pregnant women. This study was a part of the Japan Environment and Children's Study. Smoking status was assessed using questionnaires completed by participants. Information about HDP was assessed using questionnaires completed by doctors. Compared with that for women who did not smoke, women who continued smoking >10 cigarettes per day during pregnancy had a significantly higher risk of developing HDP (odds ratio: 1.58, 95% confidence interval: 1.11-2.25). In multivariate analyses with adjustment for possible confounding factors, the association still remained (odds ratio: 1.51, 95% confidence interval: 1.04-2.19). When we regarded the number of cigarettes as a continuous variable, there was a linear association between the number of cigarettes and risk of HDP, with an odds ratio of 1.02 per cigarette per day (95% confidence interval: 1.00-1.04). Smoking a greater number of cigarettes was associated with a higher risk of HDP after adjustment for possible confounding factors. Cigarette smoking cessation may avoid the complications of HDP. Our findings suggest that, in addition to the risk of small-for-gestational-age children, an increased risk of HDP should be considered in the management of pregnant women who smoke cigarettes.