Gestational outcomes of thyroid function in the first trimester

Objective: In this study, we aimed to determine the frequency of potential poor perinatal outcomes in pregnant women with thyroid dysfunction in the first trimester. Methods: A total of 1000 pregnant women whose weeks of gestation varied between 4 and 43 and who admitted to the obstetrics clinic of our hospital between 2012 and 2015 were included in our study. The pregnant women whose thyroid functions were checked in the first trimester were evaluated in terms of abortion, early preterm, late preterm, total preterm, premature rupture of membranes, intrauterine growth retardation, oligohydramnios, preeclampsia, gestational hypertension, gestational diabetes, late term pregnancy, postterm pregnancy, delivery type, 1-minute and 5-minute Apgar scores, birth weight, newborn intense care needs, and they were associated with the data of thyroid function tests in the first trimester (serum TSH, free T4, and free T3 levels). Results: In our study, hypothyroidism incidence was 8.7%, sub-clinical hypothyroidism incidence was 8.6%, hyperthyroidism incidence was 3.6% and sub-clinical hyperthyroidism incidence was 3.6% in the patients. The patients who were and were not found to have thyroid function pathology were assessed in terms of abortion, early preterm, late preterm, total preterm, intrauterine growth retardation, oligohydramnios, preeclampsia, gestational hypertension, gestational diabetes mellitus, late term pregnancy, postterm pregnancy, delivery type, 1-minute and 5-minute Apgar scores, cesarean indications and incidence, birth weight and newborn intense care needs, and no statistically significant difference was found in the patients who underwent treatment. Early rupture of membranes was observed more frequently in the group with hypothyroidism. Conclusion: Although there is no certain consensus for performing routine thyroid function test in the first trimester in endocrine study groups examining first trimester thyroid functions of pregnant women, TSH screening is considered important, especially in risky pregnant women, in countries where endemic iodine deficiency such as Turkey due to the potential harms of thyroid function pathology on fetus.