Influence of preconception carbohydrate intake on hypertensive disorders of pregnancy: The Japan Environment and Children's Study

Relationship between preconception protein intake and gestational diabetes mellitus: The Japan Environment and Children's Study

AIMS

To investigate the relationship between preconception protein intake and the risk of gestational diabetes mellitus (GDM).

METHODS

We analyzed data from the Japan Environment and Children's Study, focusing on 80,346 participants (mean age 31.3 ± 4.9 years; mean body mass index 21.2 ± 3.2 kg/m2) who delivered between 2011 and 2014. These participants had no history of diabetes mellitus, no previous diagnosis of GDM, and did not use steroids during pregnancy. Participants were categorized into five groups based on preconception protein energy ratio quintiles (Q1 and Q5 represent the lowest and highest intake, respectively). Continuous variables were compared using one-way analysis of variance or the Kruskal-Wallis test, and categorical variables using chi-square tests. Primary outcomes were GDM, early-diagnosed GDM (Ed-GDM, diagnosed at <24 weeks), and late-diagnosed GDM (Ld-GDM, diagnosed at >24 weeks). Adjusted odds ratios (aORs) and 95 % confidence intervals (CIs) were calculated using logistic regression analysis with the middle quintile (Q3) as the reference.

RESULTS

Multiple logistic regression analysis revealed that using the Q3 group as the reference, the Q5 group had a higher risk of Ed-GDM (aOR 1.48, 95 % CI 1.06-2.07), whereas the Q1 group had a lower risk of Ed-GDM (aOR 0.69, 95 % CI 0.48-0.996). However, no significant differences were observed in the risk of GDM and Ld-GDM.

CONCLUSIONS

Higher preconception protein intake was associated with increased Ed-GDM risk. Further research is needed to refine dietary recommendations for preconception protein intake.

Association between urinary cotinine level and hypertensive disorders of pregnancy in women with uterine myoma: findings from the Japan Environment and Children's Study

The effect of smoking on hypertensive disorders of pregnancy is a public concern. Recent evidence suggests that the risk of hypertensive disorders of pregnancy is influenced by the presence of uterine fibroids. We explored the association between maternal smoking exposure and the risk of hypertensive disorders of pregnancy in relation to the presence of uterine fibroids using data from Japan's largest birth cohort study. This study focused on first-time mothers, and the study population comprised 2752 and 35,294 first-time mothers with and without uterine fibroids, respectively. Hypertensive disorders of pregnancy was categorized as early-onset (before 34 weeks) and late-onset (after 34 weeks). Maternal smoking exposure was assessed by measuring the urinary cotinine concentration during the mid-trimester. Participants were classified into four quartiles based on their urinary cotinine levels as follows: Q1 (low concentration) to Q4 (high concentration). Multivariate analysis adjusted for potential confounders revealed that in women without uterine fibroids, the Q3 urinary cotinine level was associated with a modified risk of early-onset hypertensive disorders of pregnancy (adjusted odds ratio: 0.63, 95% confidence interval: 0.44-0.89). Conversely, for women with uterine fibroids, Q4 urinary cotinine level was associated with an increased risk of hypertensive disorders of pregnancy (adjusted odds ratio: 1.68, 95% confidence interval: 1.05-2.72). In conclusion, this study indicated that the impact of maternal smoking exposure varied based on the presence of uterine fibroids, underscoring the importance of personalized preconception care.

Association between preconception dietary fiber intake and hypertensive disorders of pregnancy: The Japan Environment and Children's Study

OBJECTIVES

Hypertensive disorders of pregnancy (HDP) are a significant cause of morbidity and mortality. This study aimed to investigate whether preconception dietary fiber intake is associated with new-onset HDP.

STUDY DESIGN

We identified 84,873 (primipara, 33,712; multipara, 51,161) normotensive participants from the Japan Environmental Children's Study database who delivered between 2011 and 2014. The participants were subsequently categorized into five groups based on their preconception dietary fiber intake quintiles (Q1-Q5).

MAIN OUTCOME MEASURES

The main obstetric outcome was HDP, and the secondary obstetric outcomes included early-onset (Eo, <34 weeks)-HDP, late-onset (Lo, ≥34 weeks)-HDP, small for gestational age (SGA) births, and HDP with/without SGA.

RESULTS

Multiple logistic regression analysis showed that in primiparas, the risks of HDP, Lo-HDP, and HDP without SGA were lower in the Q5 group compared with the Q3 group (HDP: adjusted odds ratio [aOR] = 0.73, 95 % confidence intervals [95 % CI] = 0.58-0.93; Lo-HDP: aOR = 0.72, 95 % CI = 0.55-0.94; and HDP without SGA: aOR = 0.68, 95 % CI = 0.53-0.88). However, the risks of Eo-HDP and HDP with SGA were higher in the Q1 group compared with the Q3 group (Eo-HDP: aOR = 1.66, 95 % CI = 1.02-2.70; and HDP with SGA: aOR = 1.81, 95 % CI = 1.04-3.17). In multiparas, the risks of Lo-HDP and SGA were higher in the Q1 group compared with the Q3 group (Lo-HDP: aOR = 1.47, 95 % CI = 1.10-1.97; SGA: aOR = 1.17, 95 % CI = 1.02-1.35).

CONCLUSIONS

Preconception dietary fiber intake is beneficial in preventing HDP onset. Therefore, new recommendations should be considered to encourage higher dietary fiber intake as part of preconception care.

Predicting postpartum hemorrhage in women undergoing planned cesarean section: A multicenter retrospective cohort study in Japan

Given Japan's unique social background, it is critical to understand the current risk factors for postpartum hemorrhage (PPH) to effectively manage the condition, especially among specific groups. Therefore, this study aimed to identify the current risk factors for PPH during planned cesarean section (CS) in Japan. This multicenter retrospective cohort study was conducted in two tertiary maternal-fetal medicine units in Fukushima, Japan and included 1,069 women who underwent planned CS between January 1, 2013, and December 31, 2022. Risk factors for PPH (of > 1000 g and > 1500 g) were assessed using multivariate logistic regression analysis, considering variables such as maternal age, parity, assisted reproductive technology (ART) pregnancy, pre-pregnancy body mass index (BMI), uterine myoma, placenta previa, gestational age at delivery, birth weight categories, and hypertensive disorders of pregnancy (HDP). Multivariate linear regression analyses were conducted to predict estimated blood loss during planned CS. ART pregnancy, a pre-pregnancy BMI of 25.0-29.9 kg/m2, and uterine myoma increased PPH risk at various levels. Maternal smoking increased the risk of >1500 g PPH (adjusted odds ratio: 3.09, 95% confidence interval [CI]: 1.16-8.20). Multivariate linear analysis showed that advanced maternal age (B: 83 g; 95% CI: 27-139 g), ART pregnancy (B: 239 g; 95% CI: 121-357 g), pre-pregnancy BMI of 25.0-29.9 kg/m2 (B: 74 g; 95% CI: 22-167 g), uterine myoma (B: 151 g; 95% CI: 47-256 g), smoking (B: 107 g; 95% CI: 13-200 g), and birth weight > 3,500 g (B: 203 g; 95% CI: 67-338 g) were associated with blood loss during planned CS. Considering a patient's clinical characteristic may help predict bleeding in planned CSs and help improve patient safety.

Association between Preconception Dietary Fiber Intake and Preterm Birth: The Japan Environment and Children's Study

Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality. Therefore, this study aimed to determine whether preconception dietary fiber intake is associated with PTB. This was a prospective cohort Japan Environmental and Children's Study (JECS). The study population comprised 85,116 singleton live-birth pregnancies from the JECS database delivered between 2011 and 2014. The participants were categorized into five groups based on their preconception dietary fiber intake quintiles (Q1 and Q5 were the lowest and highest groups, respectively). Multiple logistic regression analysis was performed to determine the association between preconception dietary fiber intake and PTB. Multiple logistic regression analysis revealed that the risk for PTB before 34 weeks was lower in the Q3, Q4, and Q5 groups than in the Q1 group (Q3: adjusted odds ratio [aOR] 0.78, 95% confidence interval [CI] 0.62-0.997; Q4: aOR 0.74, 95% CI 0.57-0.95; Q5: aOR 0.68, 95% CI 0.50-0.92). However, there was no significant difference between preconception dietary fiber intake and PTB before 37 weeks. In conclusion, higher preconception dietary fiber intake correlated with a reduced the risk for PTB before 34 weeks. Therefore, new recommendations on dietary fiber intake as part of preconception care should be considered.

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.