Retrospective analysis of the effect of antenatal corticosteroid on fetal thyroid functions in late preterm newborns

Objective: In this thesis, we aim to evaluate the effect of antenatal corticosteroid application on fetal thyroid function in the late preterm period due to preterm labor. Material and Methods: This study was carried out by retrospectively examining the data of pregnant women and newborns diagnosed with preterm labor between 34 and 37 weeks of gestation in the Department of Obstetrics and Gynecology, Faculty of Medicine, Karadeniz Technical University between 2015 and 2019. Records of a total of 99 cases were analyzed retrospectively. The cases were first divided into those who received antenatal steroid and those who were not. The cases administered antenatal steroid were divided into single dose and double dose administered cases. In total, three groups were formed. Group 1; The cases diagnosed as preterm labor between 34 and 37 weeks of gestation and who were given a single dose of antenatal steroid and gave a preterm delivery; Group 2 was the cases who were diagnosed as preterm labor between 34 and 37 weeks of gestation, double dose antenatal steroid and gave preterm delivery; Group 3 were determined as cases who were diagnosed as preterm labor between 34 and 37 weeks of gestation, delivered preterm without antenatal steroid administration. The demographic data and neonatal Thyroid Stimulating Hormone and Thyroxine levels of these groups were evaluated comparatively both with each other and within the group. Results: There was no significant difference in maternal age, gestational week and neonatal T4 level between groups. The mean Thyroid Stimulating Hormone level was significantly lower in Group 2 (p = 0.042). No significant difference was found in the mean Thyroid Stimulating Hormone and Thyroxine levels between group 1 and group 2. Conclusion: We found that maternal steroid administration in late preterm labor is associated with decreased neonatal Thyroid Stimulating Hormone levels. Keywords: Antenatal steroid, neonatal hypothyroidism, preterm labor, thyroid dysfunction