Neonatal thyroid function born to mothers living with long-term excessive iodine intake from drinking water

Summary Objective The effects of long‐term excessive maternal iodine intake on neonatal thyroid function are less known. This study aimed to assess the effects of maternal excessive iodine intake from drinking water on thyroid functions of both mothers and their neonates. Design and Methods This observational study was performed in high iodine (HI) areas and adequate iodine (AI) intake areas, including 384 healthy pregnant women in late gestation (mean week 39·3 ± 1·6 weeks) and their newborns. Blood and urine samples were obtained from pregnant women, while cord blood samples were obtained from neonates. Urinary iodine concentration (UIC) and thyroid function were evaluated. Results The median maternal UIC was 1241 and 217 μg/l in HI and AI areas, respectively (P