Impact of Subclinical Hypothyroidism in Pregnancy on Maternal and Fetal Outcomes: A Case-Control Study at a Tertiary Care Centre in Assam

Background: Subclinical hypothyroidism (SCH), marked by elevated TSH with normal free T4, is increasingly recognized as a contributor to adverse pregnancy outcomes. This study investigates the maternal and fetal outcomes in pregnant women with SCH. Methods: This prospective case-control study included 120 pregnant women, divided into 60 SCH cases and 60 euthyroid controls. TSH and FT4 were measured trimester-wise. Outcomes including gestational complications, mode of delivery, and neonatal outcomes were recorded and analyzed. Results: SCH was significantly associated with higher rates of gestational hypertension (35%), anemia (13%), and oligohydramnios (17.5%). Neonatal complications such as low birth weight (30%), NICU admissions (17.5%), and IUGR (12.5%) were more prevalent in the SCH group. The difference in TSH levels between groups was statistically significant (p < 0.001). Conclusion: SCH in pregnancy is significantly associated with adverse maternal and fetal outcomes. Early screening and appropriate levothyroxine therapy may reduce these risks.