Impact of Subclinical Hypothyroidism on Pregnancy and Newborn

Objective: The normal free T4 level together with a high TSH level is called subclinical hypothyroidism. In this study, we investigated cases of subclinical hypothyroidism diagnosed in the first trimester for possible adverse effects. The study aims to show the pregnancy outcomes and neonatal effects. Material and Methods: The study we planned was conducted retrospectively as a record study based on diagnoses. Three hospitals; one city and two state hospitals, were included in our study. Pregnant women treated at these centers between 2019 and 2021 were included the screening of newborns was similarly performed by our pediatric colleagues, based on the diagnosis in the form of scanning the files. Results: It became statistically significant when prematurity (p: 0.005), fetal weight, and week of birth were evaluated. The T4 values of the pregnant women who taken part in the study were normal, and their TSH values were ≥ 2.5-4 mIU/L. The evaluation showed that preterm birth was statistically higher and fetal weight and week of birth were significantly lower. Conclusions: In the study of pregnant women diagnosed with subclinical hypothyroidism, it was found that the preterm delivery rate was higher than in the control group, and the delivery week was also lower than in the control group.