Background: Hypothyroidism is among the most prevalent endocrine disorders encountered during pregnancy, presenting either as overt hypothyroidism (OH) or subclinical hypothyroidism (SCH). Maternal thyroid hormones are essential for maintaining normal pregnancy physiology and supporting fetal growth and neurodevelopment. Accumulating evidence suggests that thyroid dysfunction during pregnancy substantially contributes to adverse maternal and neonatal outcomes. Objective: This systematic review aims to synthesize recent evidence on the association between overt and subclinical hypothyroidism during pregnancy and their effects on maternal and fetal outcomes. Methods: A systematic search of studies published between 2015 and 2025 was conducted using PubMed, Scopus, Web of Science, and Google Scholar. Original research articles evaluating maternal and neonatal outcomes in pregnant women diagnosed with overt or subclinical hypothyroidism were included. Relevant data were extracted, reviewed, and synthesized to identify common findings and trends. Results: Reviewed studies consistently demonstrated that overt hypothyroidism is associated with increased risks of miscarriage, gestational hypertension, preeclampsia, anemia, placental abnormalities, preterm birth, and low birth weight. Neonates of affected mothers were more likely to require neonatal intensive care. Subclinical hypothyroidism, though generally less severe, was significantly associated with pregnancy loss, preterm delivery, fetal growth restriction, and neonatal complications, particularly when left untreated. Early diagnosis and appropriate levothyroxine therapy improved pregnancy outcomes. Conclusion: Both overt and subclinical hypothyroidism are important contributors to adverse maternal and fetal outcomes. Early screening, timely laboratory diagnosis, and effective management are essential. Further high-quality evidence is needed to establish standardized global screening and treatment strategies.
Singh et al. (Thu,) studied this question.