Iron intake and iron status during pregnancy and risk of congenital heart defects: A case-control study

Background The relationships between iron nutritional status and congenital heart defects (CHDs) among humans are still unclear. This study aimed to explore the associations of maternal iron intake during pregnancy and maternal and neonatal iron status with CHDs. Methods This hospital-based case-control study analyzed 474 cases and 948 controls in Shaanxi China. Eligible women waiting for delivery in the hospital were interviewed to report their diets and characteristics during pregnancy. We conveniently collected maternal blood before delivery and neonatal cord blood to get a subgroup of 50 cases and 100 controls. Mixed logistic regression models were used to estimate ORs (95%CIs) for CHDs associated with iron intake. Mixed linear regression models were used to assess the relationships between CHDs and iron status. Results Mothers whose fetuses have CHDs were less likely to have higher intakes of total iron and heme iron during pregnancy, and the tests for linear trend were significant (all P < 0.05). Mothers whose fetuses have CHDs were less likely to take iron supplements during pregnancy (OR = 0.28, 95%CI: 0.21, 0.36) and during the first trimester (OR = 0.32, 95%CI: 0.12, 0.84). Maternal SF and Hb concentrations before delivery were lower and maternal sTfR/SF before delivery was higher among the cases than the controls. Conclusions Mothers whose fetuses have CHDs are less likely to have higher intakes of total iron and heme iron and take iron supplements during pregnancy compared to their counterparts. Maternal iron status before delivery is low among mothers whose fetuses have CHDs.