Association between pre-pregnancy calcium intake and hypertensive disorders during the first pregnancy: the Japan environment and children's study

Association of parathyroid hormone with risk of hypertension and type 2 diabetes: a dose-response meta-analysis

BACKGROUND

Despite an increase in parathyroid hormone (PTH) has been reported to be associated with a higher risk of hypertension and type 2 diabetes (T2D), the comprehensive evaluation of the dose-response relationship between PTH and hypertension and T2D remains ambiguous. Therefore, a dose-response meta-analysis was performed to quantitatively investigate this association.

METHODS

PubMed, Web of Science, and Embase were systematically searched up to May 2023. Random-effect models were used to estimate the summary odds ratios (ORs) and 95% confidence intervals (CIs). Restricted cubic splines were used to model the dose-response association.

RESULTS

Ten articles (including 13 studies) were identified, with a total of 11,878 cases and 51,234 participants in the meta-analysis. Of these studies, eight (five cohort and three cross-sectional) studies investigated the association of PTH with hypertension; five (two cohort and three cross-sectional) studies assessed the association of PTH with T2D. The results showed a positive relationship between PTH and the risk of hypertension (OR,1.24, 95% CI: 1.16-1.33). We found a linear association between PTH and hypertension (Pnon-linearity= 0.222). In the dose-response analysis, the risk of hypertension increased 5% for every 10 pg/ml increase in PTH (OR,1.05, 95% CI: 1.02-1.08). The pooled OR of T2D risk for a 10 pg/ml increase in PTH was 1.00 (95% CI: 0.98-1.02).

CONCLUSIONS

Elevated PTH is associated with an increased risk of hypertension. However, the evidence of the association between PTH and T2D is limited, and more well-designed studies need to be explored.

Maternal Dietary Zinc Intake during Pregnancy and Childhood Allergic Diseases up to Four Years: The Japan Environment and Children's Study

Maternal dietary zinc intake and childhood allergy have inconsistent relationships. Thus, this study aimed to evaluate the influence of low maternal dietary zinc intake during pregnancy on developing pediatric allergic diseases. This study was designed using the Japan Environment and Children's Study dataset. The model building used data from 74,948 mother-child pairs. Maternal dietary zinc intake was estimated based on the food frequency questionnaire, collecting the intake information of 171 food and beverage items. Fitted logistic regression models and generalized estimating equation models (GEEs) estimated the association between energy-adjusted zinc intake and childhood allergic conditions. The energy-adjusted zinc intake did not affect the risk of developing allergic disorders (wheeze, asthma, atopic dermatitis, rhinitis, and food allergy) in offspring. The GEE model revealed similar insignificant odds ratios. No significant association was found between zinc intake during pregnancy and allergic diseases in offspring in early childhood. Further study remains necessary to examine the association between zinc and allergy with reliable zinc status biomarkers in the body.

Association between Gestational Weight Gain and Risk of Hypertensive Disorders of Pregnancy among Women with Obesity: A Multicenter Retrospective Cohort Study in Japan

The relationship between weight gain during pregnancy and the onset of hypertensive disorders of pregnancy in women with pre-pregnancy obesity remains unclear. We examined the effects of weight gain during pregnancy on hypertensive disorders of pregnancy among women with pre-pregnancy body mass index (BMI) ≥ 25.0 kg/m². This multicenter retrospective cohort study included nullipara women who delivered at two units in Japan between 1 January 2013, and 31 December 2020. Singleton primipara (n = 3040) were categorized into two pre-pregnancy BMI groups: 25.0-<30.0, and ≥30.0 kg/m². Using multiple logistic regression analyses (reported as adjusted odds ratio and 95% confidence interval), gestational weight gain effects on overall hypertensive disorders of pregnancy, gestational hypertension, and pre-eclampsia were determined. Gestational weight gain increased hypertensive disorders of pregnancy (1.09, 1.03-1.16, p < 0.05) and pre-eclampsia risk (1.10, 1.01-1.20, p < 0.05) among the BMI 25.0-<30.0 kg/m² group and hypertensive disorders of pregnancy risk among the ≥30.0 kg/m² group (1.07, 1.00-1.05, p < 0.05). Using receiver operating characteristic curve analyses, among the BMI 25.0-<30.0 kg/m² group, for hypertensive disorders of pregnancy (area under the curve [AUC], 0.63, p < 0.05) and pre-eclampsia (AUC, 0.62; p < 0.05), the weight gain cut-off was 10.5 and 10.6 kg, with sensitivity/specificity of 0.47/0.73 and 0.50/0.73, respectively. For the BMI ≥30.0 kg/m² group (AUC, 0.63, p < 0.05), the cut-off was 3.5 kg (sensitivity/specificity, 0.75/0.49). The optimal gestational weight gain for reducing hypertensive disorders of pregnancy among women with a pre-pregnancy BMI > 25 kg/m² may facilitate personalized pre-conception counseling among women with obesity.

Maternal triglyceride levels and neonatal outcomes: The Japan Environment and Children's Study

BACKGROUND

Although maternal triglyceride (TG) is important for fetal growth, there are few large cohort studies investigating the relationships between maternal TG during pregnancy and neonatal outcomes.

OBJECTIVES

The objective of this study was to investigate the associations between maternal TG during the second and third trimesters and neonatal outcomes including preterm birth (PTB), low birth weight (LBW), small for gestational age (SGA) and large for gestational age (LGA).

METHODS

This was a prospective birth cohort study using data of the Japan Environment and Children's Study included data of births from 2011-2014 in Japan including 79,519 pairs. Participants were divided into tertiles according to maternal TG in the second or third trimesters. Multiple logistic regression modeling was used to examine the risks of LBW, SGA, LGA and PTB in association with maternal TG levels in the second or third trimesters RESULTS: In the second trimester, compared with reference TG group (T2), women in higher TG group (T3) and lower TG group (T1) were also at increased risk of LGA (aOR 1.20, 95% CI 1.11-1.29) and SGA (aOR 1.25, 95% CI 1.10-1.41), respectively. In the third trimester, women in T3 and T1 were at increased risk of LGA (aOR 1.27, 95% CI 1.17-1.38) and SGA (aOR 1.17, 95% CI 1.02-1.34), respectively.

CONCLUSION

In this study, higher maternal TG levels in the second or third trimesters were associated with risks of LGA, however, lower maternal TG levels in the second or third trimesters were conversely associated with risks of SGA.

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.

Dietary calcium intake was related to the onset of pre-eclampsia: The TMM BirThree Cohort Study

This study aimed to explore the relationship between dietary electrolyte intake and the prevalence of hypertensive disorders of pregnancy (HDP) subtypes. Our analysis included 19 914 pregnant women from the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. A food frequency questionnaire was used to estimate dietary calcium, potassium, sodium, and magnesium intakes. HDP was determined based on the medical records during regular antenatal care. Logistic regression analysis assessed the relationship between dietary electrolytes intake quintiles, and HDP subtypes with adjustment for basic characteristics. Dietary electrolyte intakes were applied for the prediction model. Of the cohort, 547 participants delivered with pre-eclampsia (PE), 278 with superimposed PE (SP), and 896 with gestational hypertension (GH). PE was associated with low crude calcium intake (odds ratio of the first quintile [<251 mg/day] to the fifth quintile [>623 mg/day] and 95% confidence interval, 1.31 [1.00-1.70]) and P for trend was .02. SP was not associated with any nutritional intake; however, the combined outcome of PE and SP was related to low crude calcium and potassium and energy-adjusted calcium, potassium, and magnesium intakes (P for trend, .01, .048, .02, .04, and .02, respectively). The same tendency was observed for GH. A prediction model that included crude calcium and potassium intakes performed better than a model without them. In conclusion, low dietary calcium, potassium, and magnesium were associated with higher HDP subtypes prevalence. The prediction model implied that crude calcium and potassium intakes might play a critical role in PE and SP pathogenesis.

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.

Preconception Dietary Inflammatory Index and Risk of Gestational Diabetes Mellitus Based on Maternal Body Mass Index: Findings from a Japanese Birth Cohort Study

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.

Gestational weight gain as a risk factor for dystocia during first delivery: a multicenter retrospective cohort study in Japan

Background

Dystocia is a common obstetric complication among nulliparous women, which requires medical intervention and carries the risk of negative maternal and neonatal outcomes. Our aim was to examine the association between body mass index (BMI) and the occurrence of dystocia. We also identified cutoffs of gestational weight gain, based on pre-pregnancy BMI, associated with the risk of dystocia.

Methods

This was a multicenter, retrospective, cohort study conducted in two tertiary Maternal–Fetal medicine units in Fukushima, Japan. The study population included nullipara women who delivered at either of the two units between January 1, 2013, and December 31, 2020. Women (n = 2597) were categorized into six groups (G) based on their pre-pregnancy BMI: G1 (< 18.5 kg/m²), G2 (18.5 to < 20.0 kg/m²), G3 (20.0 to < 23.0 kg/m²), G4 (23.0 to < 25.0 kg/m²), G5 (25.0 to < 30.0 kg/m²), and G6 (≥ 30.0 kg/m²). Using G3 as a reference, multiple logistic regression analyses were performed to estimate the risk of dystocia for each BMI category. Receiver operating characteristic curve analyses were performed to determine the cutoff value of gestational weight gain for the risk of dystocia.

Results

The highest BMI category (G6) was an independent risk factor for dystocia (adjusted odds ratio, 3.0; 95% confidence interval, 1.5–5.8). The receiver operating characteristic curve analysis revealed no association between gestational weight gain and the occurrence of dystocia in G5 and G6 (P = 0.446 and P = 0.291, respectively). For G1 to G4, AUC and predictive cutoffs of gestational weight gain for dystocia were as follows: G1, AUC 0.64 and cutoff 11.5 kg (P < 0.05); G2, AUC 0.63 and cutoff 12.3 kg (P < 0.05); G3, AUC 0.67 and cutoff 14.3 kg (P < 0.01); and G4, AUC 0.63 and cutoff 11.5 kg (P < 0.05).

Conclusion

A pre-pregnancy BMI > 30.0 kg/m² was an independent risk factor for dystocia. For women with a pre-pregnancy BMI < 25.0 kg/m², the risk of dystocia increases as a function of gestational weight gain. These findings could inform personalized preconception care for women to optimize maternal and neonatal health.

Optimal gestational weight gain to reduce the risk of hypertension disorders of pregnancy among women with obesity: A single tertiary referral center study in Japan

AIM

To examine the effect of weight gain during pregnancy on hypertension disorders of pregnancy among women with a prepregnancy body mass index ≥30.0 kg/m² .

METHODS

This retrospective cohort study included 257 Japanese women (116 primipara; 141 multipara) with singleton pregnancies with a prepregnancy body mass index ≥ 30.0 kg/m² , who gave birth during 2013 to 2020 at Ohta Nishinouchi Hospital. Multiple logistic regression analyses were performed to identify the effect of gestational weight gain on early-onset (<34 weeks), late-onset (≥34 weeks), and overall hypertension disorders of pregnancy.

RESULTS

The prevalence of hypertension disorders of pregnancy in primiparas and multiparas was 28.4% and 11.3%, respectively. By multiple logistic regression analysis, gestational weight gain during pregnancy increased the risk of early-onset (adjusted odds ratio: 1.20, 95% confidence interval: 1.03-1.39, p < 0.05) and overall hypertension disorders of pregnancy (adjusted odds ratio: 1.12, 95% confidence interval: 1.03-1.22, p < 0.05) among primiparas. Based on receiver operating characteristic curve analyses for early-onset (area under the curve 0.67, 95% confidence interval: 0.56-0.78; p < 0.05) and overall hypertension disorders of pregnancy (area under the curve 0.76, 95% confidence interval: 0.61-0.91; p < 0.05) among primiparas, we determined the cut-off weight gain during pregnancy for early-onset and overall hypertension disorders of pregnancy as 3.85 kg, with sensitivity/specificity of 0.76/0.59 and 0.91/0.53, respectively.

CONCLUSION

We recommend that the optimal gestational weight gain for reducing HDP be under 3.85 kg. This information may facilitate personalized pre-conception counseling among women with obesity.

Hypertensive disorders of pregnancy: definition, management, and out-of-office blood pressure measurement

Hypertensive disorders of pregnancy increase the risk of adverse maternal and fetal outcomes. In 2018, the Japanese classification of hypertensive disorders of pregnancy was standardized with those of other countries, and a hypertensive disorder of pregnancy was considered to be present if hypertension existed during pregnancy and up to 12 weeks after delivery. Strategies for the prevention of hypertensive disorders of pregnancy have become much clearer, but further research is needed on appropriate subjects and methods of administration, and these have not been clarified in Japan. Although guidelines for the use of antihypertensive drugs are also being studied and standardized with those of other countries, the use of calcium antagonists before 20 weeks of gestation is still contraindicated in Japan because of the safety concerns that were raised regarding possible fetal anomalies associated with their use at the time of their market launch. Chronic hypertension is now included in the definition of hypertensive disorders of pregnancy, and blood pressure measurement is a fundamental component of the diagnosis of hypertensive disorders of pregnancy. Out-of-office blood pressure measurements, including ambulatory and home blood pressure measurements, are important for pregnant and nonpregnant women. Although conditions such as white-coat hypertension and masked hypertension have been reported, determining their occurrence in pregnancy is complicated by the gestational week. This narrative review focused on recent reports on hypertensive disorders of pregnancy, including those related to blood pressure measurement and classification.

Effect of gestational weight gain on preeclampsia among underweight women: A single tertiary referral center study in Japanese women

AIM

To examine the effect of weight gain during pregnancy on preeclampsia among women with a prepregnancy body mass index < 18.5 kg/m² .

METHODS

This retrospective cohort study included 479 Japanese women with singleton pregnancies and a prepregnancy body mass index < 18.5 kg/m² , who gave birth between 2013 and 2019 at Ohta Nishinouchi Hospital. The study included 22 (18 with preeclampsia and four with gestational hypertension) and 457 patients with and without hypertensive disorders of pregnancy, respectively.

RESULTS

The prevalence of hypertensive disorders of pregnancy and preeclampsia was 4.6% and 3.8%, respectively. With weight gain during pregnancy (continuous variable) set as a reference, multiple logistic regression revealed that excessive weight gain during pregnancy increased the risk of preeclampsia (adjusted odds ratio: 1.13, 95% confidence interval: 1.00-1.28, p < 0.05) and hypertensive disorders of pregnancy (adjusted odds ratio: 1.15, 95% confidence interval: 1.03-1.29, p < 0.05). Based on receiver operating characteristic curve analyses (area under the curve 0.65, 95% confidence interval: 0.50-0.80; p < 0.05), we determined the cutoff value of weight gain during pregnancy for the occurrence of preeclampsia among women with body mass index < 18.5 kg/m² to be 13.0 kg, with sensitivity and specificity of 0.50 and 0.78, respectively.

CONCLUSION

This study indicates that excessive weight gain during pregnancy increases preeclampsia risk among underweight women and provides new recommendations for weight gain during pregnancy for such women. Further research regarding the pathogenesis of preeclampsia for underweight women is warranted.

Adverse obstetric outcomes in early-diagnosed gestational diabetes mellitus: The Japan Environment and Children's Study

AIMS/INTRODUCTION

To examine adverse outcomes in women with early-diagnosed gestational diabetes mellitus using data from a large birth cohort study in Japan.

MATERIALS AND METHODS

This study analyzed data from singleton pregnancies in the Japan Environment and Children's Study including births during 2011-2014. Mothers with an HbA1c level ≥6.5% in the first trimester, a history of diabetes mellitus, or steroid use during pregnancy were excluded. The participants were divided into three groups: control (without gestational diabetes mellitus), early-diagnosed gestational diabetes mellitus (diagnosed before gestational week 24), and late-diagnosed gestational diabetes mellitus (diagnosed after gestational week 24). Multiple logistic regression analysis was performed to calculate the risk of early-diagnosed and late-diagnosed gestational diabetes mellitus for adverse obstetrics outcomes.

RESULTS

In total, 100,376 eligible participants were included in this study. The number of individuals in control cases, early-diagnosed gestational diabetes mellitus cases, and late-diagnosed gestational diabetes mellitus cases was 98,090 (97.7%), 751 (0.7%), and 1,535 (1.5%), respectively. When control cases were used as reference, multiple logistic regression analysis revealed that early-diagnosed gestational diabetes mellitus increased the risk of hypertensive disorders of pregnancy (adjusted odds ratio: 2.08, 95% confidence interval: 1.51-2.86), early-onset hypertensive disorders of pregnancy (adjusted odds ratio: 1.91, 95% confidence interval: 1.01-3.65), and late-onset hypertensive disorders of pregnancy (adjusted odds ratio: 1.92, 95% confidence interval: 1.29-2.86).

CONCLUSION

Early-diagnosed gestational diabetes mellitus is associated with serious obstetric complications. Our findings indicate the necessity of further investigations to validate the benefit of early screening for gestational diabetes mellitus in pregnant women.

Age at menarche and risk of adverse obstetric outcomes during the first childbirth in Japan: The Japan Environment and Children's Study

AIM

Age at menarche is used as a risk indicator of gestational diabetes mellitus, preterm birth, and fetal growth. However, little is known regarding the age impact on obstetric outcomes among nulliparous women. This study investigated whether menarche age was correlated with obstetric outcomes among nulliparous women.

METHODS

We analyzed the data obtained for 37 645 singleton pregnancies between 2011 and 2014 in the Japan Environment and Children's Study. Age at menarche was categorized into the ≤9-, 10-, 11-, 12-, 13-, 14-, and ≥15-year-old groups (n = 363, 3155, 8390, 11 164, 6713, 5446, and 2414, respectively). We calculated the relative risk for cases of preterm birth <37 weeks, low birthweight <2500 g, small for gestational age, early and late-onset hypertension disorders of pregnancy, and early- and late-diagnosed (diagnosed < or ≧ 24 weeks) gestational diabetes mellitus using a reference of 12 years at menarche.

RESULTS

Women with an age at menarche ≤9 years showed an increased incidence of developing early-diagnosed gestational diabetes mellitus (relative risk: 2.42; 95% confidence interval: 1.05-5.60). A high body mass index before pregnancy increased the risk of developing gestational diabetes mellitus.

CONCLUSIONS

Age at menarche helped in assessing the risk of early-diagnosed gestational diabetes mellitus among nulliparous women. Future studies are needed to clarify the underlying mechanisms. This study is the first to use data from the largest prospective birth cohort study of Japan and to investigate the relationship between menarche age and obstetric outcomes among nulliparous women.

Association of maternal pre-pregnancy dietary intake with adverse maternal and neonatal outcomes: A systematic review and meta-analysis of prospective studies

This study aimed to summarize the evidence regarding the effects of dietary intake before conception on pregnancy outcomes by performing a systematic review and meta-analysis of prospective studies. Electronic databases were searched from inception up to August 2021. Overall, 65 studies involving 831 798 participants were included and 38 studies were quantitatively pooled. With regard to maternal outcomes, pre-pregnancy intake of fried food, fast food, red and processed meat, heme iron and a low-carbohydrate dietary pattern was positively associated with the risk of gestational diabetes mellitus (GDM) (all P < 0.05). However, a high dietary fiber intake and folic acid supplementation were negatively associated with GDM risk (both P < 0.05). With regard to neonatal outcomes, maternal caffeine intake before pregnancy significantly increased the risk of spontaneous abortion, while folic acid supplementation had protective effects on total adverse neonatal outcomes, preterm birth, and small-for-gestational age (SGA, all P < 0.05). However, no significant associations were found between adverse pregnancy outcomes (i.e., GDM and SGA) and the pre-pregnancy dietary intake of sugar-sweetened beverages, potato, fish, and carbohydrates and the Healthy Eating Index. Our study suggests that maintaining a healthy diet before conception has significant beneficial effects on pregnancy outcomes.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.1989658.

Effect of gestational weight gain on placental weight: A single tertiary referral center study of Japanese women

AIM

The effect of gestational weight gain on placental weight has not been elucidated. We aimed to examine the effect of body weight gain during pregnancy on the Japanese standardized z-score of placental weight, based on the pre-pregnancy body mass index.

METHODS

This retrospective cohort study included Japanese women with singleton pregnancies who gave birth during 2013-2019 at Ohta Nishinouchi Hospital. Participants (n = 3610) were categorized by their pre-pregnancy body mass index: G1 (<18.5 kg/m² ), G2 (18.5 to <20.0 kg/m² ), G3 (20.0 to <23.0 kg/m² ), G4 (23.0 to <25.0 kg/m² ), and G5 (≥25.0 kg/m² ). Multiple linear regression analysis was used to identify associations between insufficient or excessive gestational weight gain in each body mass index category and z-score of placental weight, with adjustments for maternal age, assisted reproductive technology, and maternal pre-pregnancy conditions, such as hypertension, diabetes mellitus, myoma uteri, and uterine anomalies.

RESULTS

Among the 3610 women assessed, 479, 692, 1292, 435, and 711 were in G1-G5, respectively. In G1, G3, and G4, excessive weight gain increased the placental weight z-score ([B: 0.50, 95% confidence interval [CI]: 0.23-0.76], [B: 0.19, 95% CI: 0.19-0.33], and [B: 0.18, 95% CI: 0.10-0.26]). Insufficient weight gain decreased the placental weight z-score in G3 (B: -0.19, 95% CI: -0.33 to -0.06) and G4 (B: -0.21, 95% CI: -0.29 to -0.13) women.

CONCLUSION

The effect of weight gain during pregnancy on placental size varies by pre-pregnancy body mass index. This result may guide personalized pre-conception counseling to improve the outcomes of offspring.

Immunoglobulin E levels and pregnancy-induced hypertension: Japan Environment and Children's Study

High serum immunoglobulin E (IgE) levels are associated with cardiovascular events. We aimed to evaluate the association between total IgE levels during the first trimester of pregnancy and pregnancy-induced hypertension (PIH) development in a large Japanese cohort. We analysed data pertaining to singleton primipara pregnancies recorded in the Japan Environment and Children's Study involving births from 2011 to 2014. Serum IgE levels were determined using the immunonephelometric technique. High serum IgE was defined as level ≥ 170 IU/ml. Hypertensive disorders in pregnancy (HDP) were categorized into early onset (Eo) PIH (developed < 34 weeks) or late onset (Lo) PIH (developed ≧ 34 weeks). A multiple logistic regression model was used to estimate the risk of high serum IgE levels on PIH, Eo-PIH, and Lo-PIH. Overall, 32,518 participants were enrolled. The prevalence of total, Eo-, and Lo-PIH was 3.2%, 0.6%, and 2.3%, respectively. Patients with high serum IgE levels had an increased risk of Lo-HDP (adjusted odds ratio [aOR]:1.19, 95% confidence interval 1.01-1.40). No correlation was found with either PIH (total) or Eo-PIH. High serum IgE levels during the first trimester were associated with the risk of Lo-PIH. Our results could influence and shape further research regarding the pathogenesis of Lo hypertension.