We aimed to determine the risk of perinatal complications during delivery in mothers with non-normal glucose tolerance in a large Japanese birth cohort. We analysed data of 24,295 neonate–mother pairs in the Japan Environment and Children’s Study cohort between 2011 and 2014. We included 67 mothers with type 1 diabetes, 102 with type 2 diabetes (determined by questionnaire), 2,045 with gestational diabetes (determined by diagnosis), and 2,949 with plasma glucose levels ≥140 mg/dL (shown by a screening test for gestational diabetes). Gestational age, birth weight, placental weight, and proportions of preterm birth, and labour and neonatal complications at delivery in mothers with diabetes were compared with those in mothers with normal glucose tolerance. Mean gestational age was shorter in mothers with any type of diabetes than in mothers without diabetes. Birth weight tended to be heavier in mothers with type 1 diabetes, and placental weight was significantly heavier in mothers with type 1 and gestational diabetes and elevated plasma glucose levels (all p<0.05). The relative risks of any labour complication and any neonatal complication were 1.49 and 2.28 in type 2 diabetes, 1.59 and 1.95 in gestational diabetes, and 1.22 and 1.30 in a positive screening test result (all p<0.05). The relative risks of preterm birth, gestational hypertension, and neonatal jaundice were significantly higher in mothers with types 1 (2.77; 4.07; 2.04) and 2 diabetes (2.65; 5.84; 1.99) and a positive screening test result (1.29; 1.63; 1.12) than in those without diabetes (all p<0.05). In conclusion, placental weight is heavier in mothers with non-normal glucose tolerance. Preterm birth, gestational hypertension, and jaundice are more frequent in mothers with types 1 and 2 diabetes. A positive result in a screening test for gestational diabetes suggests not only a non-normal glucose tolerance, but also a medium (middle-level) risk of perinatal complications.

Background: Unplanned pregnancy is a public health issue with adverse consequences for maternal and neonatal health. In Japan, the prevalence of unplanned pregnancy was 46.2% in 2002. However, few studies have investigated this topic, and there is little recent data from Japan. We described and examined the prevalence and determinants of unplanned pregnancy among rural women in Japan from 2011 to 2016. Methods: We used cross-sectional data from a community-based cohort study (Project Koshu). Data were collected from 2011 to 2016 via a self-report questionnaire included in the Maternal and Child Health Handbook of Japan. Pregnancy intention was measured as a binary variable (planned or unplanned). Univariate and multivariate logistic regression analyses were performed to examine factors associated with unplanned pregnancy, with results reported as odds ratios (ORs) and 95% confidence intervals (CIs). We conducted sensitivity analyses with different definitions of pregnancy intention to assess the robustness of the results. The significance level was set at 5%. Results: Of the 932 participants (mean ± standard deviation age at baseline: 31.3 ± 5.2 years), 382 (41%) pregnancies were reported as unplanned. The multivariate analyses showed that maternal age (+ 1 year: OR = 0.94, 95% CI: 0.92–0.97, p < 0.001), ‘other’ family structure (OR = 2.76, 95% CI: 1.12–6.76, p = 0.03), three or more pregnancies (OR = 2.26, 95% CI: 1.66–3.08, p < 0.001), current smoking (OR = 2.60, 95% CI: 1.26–5.35, p = 0.01), balanced diet (OR = 0.62, 95% CI: 0.47–0.83, p < 0.001) and current depression (OR = 1.63, 95% CI: 1.24–2.16, p < 0.001) were strongly associated with unplanned pregnancy. These associations were consistent across definitions of pregnancy intention, supporting the robustness of our results. Conclusions: The prevalence of unplanned pregnancy in the study population was high (41%). Risk factors for unplanned pregnancy were age, number of pregnancies, smoking, having a balanced diet and current depression. These results suggest greater efforts are needed to enhance sex education for young people, improve access to family planning services and provide comprehensive health care for high-risk women to help reduce unplanned pregnancies.

Background Disinfectants are widely used in the medical field, particularly recently because of the coronavirus pandemic, which has led to an increase in their use by both medical professionals and the general population. The objective of this study was to examine whether occupational disinfectant use during pregnancy was associated with the development of allergic disease in offspring at 3 years. Methods We used data from 78 915 mother/child pairs who participated in the Japan Environment and Children’s Study, which is a prospective birth cohort recruited between January 2011 and March 2014. We examined the associations between maternal disinfectant use during pregnancy and allergic diseases (asthma, eczema and food allergies) in children after adjustment for covariates including maternal postnatal return to work when the child was 1 year old by multivariate logistic regression. Results Compared with those who never used disinfectants, participants who used disinfectant every day had a significantly higher risk of asthma in their offspring (adjusted OR 1.18, 95% CI 1.05 to 1.33 for 1–6 times a week; adjusted OR 1.26, 95% CI 1.05 to 1.52 for every day). The associations between disinfectant exposure and eczema were similar to those of asthma (adjusted OR 1.16, 95% CI 1.02 to 1.31 for 1–6 times a week; adjusted OR 1.29, 95% CI 1.06 to 1.57 for every day). We found a significant exposure-dependent relationship (p for trend <0.01). There were no significant associations between disinfectant use and food allergies. Conclusion Disinfectant use by pregnant women may be a risk factor for asthma and eczema in offspring. As disinfectants are an effective tool in the prevention of infectious diseases, replication of this study and further research into the mechanisms are warranted.

The hygiene hypothesis assumes a low incidence of allergic diseases in families engaging in farming work. However, a few studies have indicated rural life as a potential risk factor for atopic dermatitis (AD). Using a large Japanese birth cohort dataset, we calculated the accumulated incidence of AD in children aged 6 months and 1, 2, and 3 years by family business and the hazard ratio. We adjusted for confounding factors. The father’s job was considered the family business. We analysed data on 41,469 father–child pairs at 6 months of age, 40,067 pairs at 1 year, 38,286 pairs at 2 years, and 36,570 pairs at 3 years. We found the highest accumulated incidence of AD among children with fathers engaged in primary industry, with 2.5% at the age of 6 months, 6.6% at 1 year, 12.0% at 2 years, and 15.4% at 3 years. Among primary industry occupations, forestry was associated with the highest incidence of AD across these ages. The hazard ratio of AD was also highest for children whose family business was primary industry. In conclusion, the highest incidence and hazard ratio of AD were observed among children whose fathers worked in primary industry.