Associations between maternal complications during pregnancy and childhood asthma: a retrospective cohort study in southern China

Abstract The associations between maternal complications during pregnancy and childhood asthma have rarely been investigated in low and middle-income countries. This study investigated the associations among the southern Chinese population using data from the Physical Health Monitoring Project of Primary and High School Students in Guangzhou. Information on maternal gestational hypertension, gestational diabetes, gestational anemia, and hepatitis B during pregnancy was extracted from medical records. Ever diagnosis of asthma of the child was obtained by questionnaire. Binomial logistic regression models were used to estimate the adjusted odds ratios (aORs) and 95% confidential interval (CI) for childhood asthma. Mediation analyses were used to estimate the indirect effects of gestational complications on childhood asthma mediated through preterm birth, cesarean delivery, low birth weight, and non-breastfeeding in the first 6 months. We included 208,190 children, gestational hypertension, gestational diabetes, gestational anemia, or hepatitis B during pregnancy was positively associated with ever diagnosed childhood asthma, with the aOR of 1.66(95%CI 1.31–2.10), 1.68(95%CI 1.40–2.02), 1.69(95%CI 1.49–1.91) and 1.54(95%CI 1.13–2.08), respectively. A stronger association was observed for 2 or more gestational complications (aOR = 2.34, 95%CI 1.71–3.23) than 1 gestational complication (aOR = 1.80, 95%CI 1.62–1.99). A small proportion of the associations were mediated through preterm birth, cesarean delivery, low birth weight, and non-breastfeeding in the first 6 months. Gestational hypertension, diabetes, anemia, or hepatitis B during pregnancy was significantly associated with childhood asthma in the southern Chinese population, and the associations were partially explained by the mediated effects of cesarean delivery, preterm birth, low birthweight and non-breastfeeding in the first 6 months.