Birth weight and the role of maternal thyroid hormones in females attending Al-Alkhadimiya Teaching Hospital in Baghdad

BACKGROUND: All human tissue metabolism and fetal development require thyroid hormone. Early placental transfer of maternal thyroid hormones impacts fetal thyroid hormone availability. The fetal thyroid gland grows in the 18th to 20th week, yet maternal thyroid hormones still affect it. The study examines the relationship between maternal thyroid hormones, BMI, and birth weight.METHODS: Cross-sectional study of 110 late-pregnant women at Al-Alkhadimiya Teaching Hospital from January 1st, 2021, to January 1st, 2022, asking about age, gestational age (GA), weight, and height to determine BMI and WHO BMI classification. All females had TSH, free T3, and free T4 tests. Finally measured infant weight.RESULTS: In a study of 110 pregnant women with an average BMI of 27±5 kg/m2 and age 24±6 years, 45.45% were obese and 54.55% were under 20. Obese women more often had natural births and delivered heavier babies, especially those aged 31-45. Fetal weight was influenced by maternal BMI, age, and T3, but not FT4 or TSH.CONCLUSIONS: Maternal thyroid hormones, especially free T3, influence fetal growth and delivery outcomes. Maternal obesity and age can impact fetal development and birth weight. While maternal BMI, age, and TSH relate to fetal weight, FT4 and TSH levels don’t. Proper weight management based on BMI is crucial for the health of both mother and baby.