Gestational anemia (GA) is a global health concern with a remarkably high prevalence in Japan, which is associated with various maternal and neonatal outcomes. This study aimed to explore whether GA and non-anemic iron deficiency (NAID) during the third trimester is associated with maternal characteristics, nutrient intake, low birth weight (LBW), and preterm birth. Participants were categorized into GA, NAID, and normal groups, based on serum ferritin and hemoglobin levels. Nutrient intake was assessed using the Brief Diet History Questionnaire. Data from 317 pregnant women were analyzed, including 110 (34.7%), 151 (47.6%), and 56 (17.6%) women in the GA, NAID, and normal groups, respectively. Factors associated with GA included being multipara (p < 0.001) and not taking any type of iron supplements in the third trimester (p = 0.043). The normal group had a significantly higher proportion of preterm birth and LBW than the GA and NAID groups. The GA group had a significantly higher energy intake than the normal group (p = 0.044). Overall, energy and micronutrient intake were significantly below the estimated average requirement in the dietary reference intakes for Japanese. Health care professionals need to consider nutritional advice that can prevent GA by focusing on overall micronutrients, not just energy intake.

Inadequate gestational weight gain (GWG) is associated with birth weight and premature birth and is a primary problem in Asia, particularly in Japan. This study aimed to identify the risk factors associated with inadequate GWG, focusing on women's target GWG and advised GWG by healthcare professionals. A questionnaire for women in their second trimester inquired about their target GWG and advice regarding GWG by healthcare professionals. Of the 626 participants, 52.6% were classified in the inadequate GWG group. Inadequate GWG was associated with a prepregnancy body mass index (BMI) < 18.5 kg/m² and weight below the prepregnancy weight in the second trimester. Among the multiparas, inadequate GWG was associated with an individual target GWG below the guideline, with no advice from healthcare professionals, and with an advised GWG below the guideline. Among the primiparas, there were no significant differences in the individual targets or advised GWG. Healthcare professionals must understand the latest guidelines regarding GWG and apply them when advising women. The importance of preconception care in achieving a BMI of at least 18.5 kg/m² before pregnancy is also suggested.

Nausea and vomiting in pregnancy (NVP) is a common symptom. Although the influence of NVP during the first trimester on dietary intake and birth outcomes has been revealed, no study has focused on NVP during the second trimester. This study aimed to reveal whether NVP severity during the second trimester is associated with dietary intake, gestational weight gain (GWG), birth weight, and delivery week. Participants completed a questionnaire at 18–27 gestational weeks. NVP severity was assessed using the modified Pregnancy-Unique Quantification of Emesis and Nausea scale in the questionnaire. Dietary habits were assessed using a brief-type diet history questionnaire. In total, 825 responses were analyzed: 202 (24.5%), 135 (16.4%), and 8 (1.0%) women reported mild, moderate, and severe NVP, respectively; 480 (58.2%) women did not have NVP during the second trimester. No significant association was observed between energy and nutrient intake and no/mild and moderate/severe NVP. Women with moderate/severe NVP had lower total GWG than those with no/mild NVP (p = 0.007). There was no significant difference in low birth weight and preterm birth rates (p = 0.246 and p = 0.604). This is the first study to investigate whether NVP severity during the second trimester is associated with dietary intake and birth outcomes.

The prevalence of low-birth-weight infants has increased over the past 40 years to approximately 9–10% of Japanese live births. This study aims to identify healthy lifestyle behaviors and psychosocial factors contributing to appropriate perinatal outcomes, gestational weight gain, and postpartum weight change. The Japan Pregnancy, Eating, Activity, and Cohort study was initiated in 2020 in Tokyo, Yamagata/Miyagi, Osaka, and Fukuoka. Participants will be enrolled at approximately 12 weeks of gestation, with follow-up at 18–27 and 35–41 weeks of gestation and 1, 6, and 12 months postpartum. Approximately 3000 participants are targeted: Yamagata/Miyagi (n = 300), Tokyo (n = 1500), Osaka (n = 800), and Fukuoka (n = 400). Participants will complete questionnaires on healthy lifestyle behaviors (dietary intake, physical activity, and circadian rhythm), psychosocial factors, weight control, and behavioral intentions. Medical records will be reviewed for antenatal checkup data. The primary outcomes will include gestational weight gain, infant birth weight, perinatal complications, breastfeeding, and postpartum weight change. Demographic and psychosocial factors and lifestyle behaviors will be examined as covariates and potential confounders. Biological samples will be collected in Tokyo and Yamagata. The study’s findings will inform efforts to improve perinatal care guidelines through evidence-based recommendations.

This study examined the association of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake during the second trimester with low birth weight (LBW) in pregnant Japanese women and was conducted in conjunction with the Japan Pregnancy Eating and Activity Cohort (J-PEACH) study. The study included 504 pregnant women from four Japanese sites. During the second trimester (14–27 weeks), the participants filled out a self-administered questionnaire assessing the frequency of DHA and EPA supplement intake in the past month, as well as a brief-type self-administered diet history questionnaire (BDHQ). The analysis involved data from two time points: responses to the BDHQ and infant data at birth. In total, 471 and 33 participants were classified into the normal birth weight and LBW groups, respectively. The participants were divided into high-, medium-, and low-intake groups based on their total dietary and EPA and DHA supplementary intakes. The Cochran–Armitage trend test was used to analyze the data; the prevalence of LBW was higher in the low-intake group (p = 0.04). There was no significant sex-based trend (p = 0.27 and p = 0.35). In Japanese women, low dietary and supplementary EPA and DHA intake until the second trimester were risk factors for LBW.

Aim: To determine the effect of maternal egg consumption during lactation on the development of egg allergies in 12‐month‐old infants. We hypothesized that infants whose mothers consume larger amounts of eggs during the early lactation period acquire oral immune tolerance and are less likely to develop egg allergies at 12 months.Methods: This study was a part of the Japan Pregnancy Eating and Activity Cohort Study. Mothers answered questionnaires on egg consumption, breastfeeding rates at 1 month, infants' eczema at 6 months, and the development of egg allergies among infants at 12 months. In order to assess the actual impact of maternal egg consumption on infants' egg allergy development, breastfeeding‐dependent egg consumption was calculated at 1 month by multiplying maternal egg consumption at 1 month with the breastfeeding rates at the same time. Logistic regression analysis was performed to examine the potential risk and protective factors.Results: Data from 420 infants were analyzed, of whom 27 had egg allergies at 12 months. No significant impact of breastfeeding‐dependent egg consumption was observed on infants' egg allergy development at 12 months. However, infants with eczema at 6 months showed a greater risk of developing an egg allergy at 12 months (adjusted odds ratio, 3.59; 95% confidence interval, 1.59–8.13).Conclusion: The results suggest that breastfeeding‐dependent egg consumption at 1 month did not contribute to sufficient oral immune tolerance in 12‐month‐old infants. Eczema at 6 months significantly impacted the development of an egg allergy, emphasizing the importance of preventing cutaneous exposure to egg allergens.