Maternal thyroid function with placental hemodynamics and their effect on fetal and maternal outcomes

Abstract

Objectives To evaluate the relationship between maternal mild fluctuation in thyroid hormones not amounting to hypothyroidism or hyperthyroidism and altered fetoplacental hemodynamic changes allowing early detection of adverse maternal and perinatal outcomes. Background Suboptimal placental function is associated with preeclampsia and intrauterine growth restriction. Studies suggested that thyroid hormones play a role in placental development through the effects on trophoblastic invasion. Patients and methods A prospective cohort study, included 123 healthy pregnant women recruited from the antenatal care in Obstetrics and Gynecology Department, at Menoufia University Hospital and Damas Central Hospital, from October 2018 till August 2019. Free thyroxine (FT4) concentrations and thyroid-stimulating hormone were measured in early pregnancy (at 9 and 18 weeks). Placental function was measured by Doppler ultrasound measuring umbilical artery pulsatility index and uterine artery resistance index (between 18–23 and 28–32 gestational weeks). Results The data of 123 patients were analyzed. Increased FT4 concentration in early pregnancy was associated with higher vascular resistance in the second and third trimesters in both umbilical artery pulsatility index and uterine artery resistance index. These effects on placental function may demonstrate the association of FT4 with pregnancy outcomes, such as preeclampsia and birth weight. Conclusion The data shows that increased) FT4 concentration in early pregnancy is associated with placental vascular function during the second and third trimesters. Other pregnancy-associated complications are preeclampsia and low birth weight.