Association of Chlamydia trachomatis infection with pregnancy outcomes among Japanese pregnant women: The Japan environment and children's study.

This study aimed to investigate the impact of Chlamydia trachomatis (CT) infection on pregnancy outcome in pregnant Japanese women. We utilized the data from a nationwide birth cohort study, the Japan Environment and Children's Study (JECS), for this study. We enrolled 26,385 individuals who could refer to data on pregnancy outcomes and confounding factors, with data on CT. Binominal logistic regression models were used to determine whether pregnant women with CT positivity were at more risk of experiencing adverse pregnancy outcomes, preterm birth (PTB), preterm prelabor rupture of membrane (pPROM), low birth weight (LBW) infants, small for gestational age (SGA) births, or hypertensive disorders of pregnancy (HDP). After adjusting for maternal age, parity, marital status, smoking status, and education status, there were no significantly increased risks of PTB, pPROM, LBW infants, SGA, and HDP in the odds ratios. No significant increase in the risk of adverse pregnancy outcomes was observed in any of the subgroup analyses, which were limited to the pregnancy women in Fukushima prefecture, where CT screening could be confirmed at 28-30 weeks of gestation. We believe that the results of this study will make a significant contribution to the future of medical care for pregnant women in Japan. Our findings are important for medical practitioners to contribute to the future medical treatment of Japanese pregnant women, and also to contribute to pre-conception care for Japanese society as a whole, including pregnant women.

Impact of preconception sodium intake on hypertensive disorders of pregnancy: The Japan Environment and Children's study.

OBJECTIVES: Determining the appropriate preconception care to reduce the occurrence of hypertensive disorders of pregnancy (HDP) remains a challenge in modern obstetrics. We aimed to examine the association between pre-pregnancy sodium (Na) intake and the development of HDP in normotensive women. STUDY DESIGN: From the Japan Environment and Children's study (JECS) database, we identified 85,152 normotensive Japanese women who were recruited to the JECS between January 2011 and March 2014. Participants were categorized into five groups according to pre-pregnancy Na intake quintiles (Q1 and Q5 were the lowest and highest Na intake groups, respectively). MAIN OUTCOME MEASURES: Multiple logistic regressions were performed to identify the effect of pre-pregnancy Na intake on HDP, early-onset (<34 weeks) HDP, late-onset (34 ≥ weeks) HDP, and HDP with/without small for gestational age (SGA). RESULTS: Using Q3 (the middle Na intake group) as the reference, multiple logistic regression showed that both the lowest (Q1) and highest (Q5) Na intake groups had an increased risk of HDP with SGA [adjusted odds ratio (aOR): 1.50, 95% confidence interval (CI): 1.02-2.21 and aOR: 1.52, 95% CI: 1.03-2.24, respectively]. CONCLUSIONS: Both lower and higher Na intake before pregnancy increases the risk of HDP with SGA in normotensive Japanese women. This finding may indicate new recommendations for Na intake before pregnancy to prevent HDP.

Teenage pregnancy as a risk factor for placental abruption: Findings from the prospective Japan environment and children's study.

OBJECTIVE: Placental abruption is a significant obstetric complication that affects both maternal and neonatal mortality and morbidity. The present study examined the effect of maternal age on the incidence of placental abruption. METHODS: We used data of singleton pregnancies from the Japan Environment and Children's Study, which was a prospective birth cohort study conducted between January 2011 and March 2014 across 15 regional centers in Japan. A multiple regression model was used to identify whether maternal age (<20 years, 20-24 years, 25-29 years, 30-34 years, and ≥35 years) is a risk factor for placental abruption. The analyses were conducted while considering the history of placental abruption, assisted reproductive technology, number of previous deliveries, smoking during pregnancy, body mass index before pregnancy, and chronic hypertension. RESULTS: A total of 94,410 Japanese women (93,994 without placental abruption and 416 with placental abruption) were recruited. Herein, 764, 8421, 25915, 33517, and 25793 women were aged <20 years, 20-24 years, 25-29 years, 30-34 years, and ≥35 years, respectively. Besides advanced maternal age (≥35 years; adjusted odds ratio: 1.7, 95% confidence interval: 1.1-2.5), teenage pregnancy was also a risk factor for placental abruption (adjusted odds ratio: 2.8, 95% confidence interval: 1.2-6.5) when the maternal age of 20-24 years was set as a reference. CONCLUSIONS: In the Japanese general population, besides advanced maternal age, teenage pregnancy was associated with placental abruption. Recently, the mean maternal age has been changing in Japan. Therefore, it is important for obstetric care providers to provide proper counseling to young women based on up-to-date evidence.