Management of Hypothyroidism in Pregnancy and Its Impact on Maternal and Perinatal Outcomes: A Single-Center Retrospective Cohort Study

Background: Hypothyroidism is one of the most common endocrine conditions during pregnancy and has been associated with poor obstetric and perinatal outcomes. There is still a lack of data from Middle Eastern populations, despite its clinical significance. This study aimed to evaluate thyroid management patterns during pregnancy and examine the association between thyroid function control and maternal and perinatal outcomes in women with hypothyroidism at a tertiary care center in Qatar. Methods: A retrospective cohort study including 379 pregnant women with hypothyroidism diagnosed between January 2019 and November 2022 was conducted at Sidra Medicine in Doha, Qatar. Based on trimester-specific Thyroid-stimulating hormone (TSH )reference values, participants were categorized as having adequately or inadequately controlled thyroid function. Data on obstetrics, biochemistry, and demographics were taken from electronic medical records (EMR). Statistical analyses were performed using chi-square tests for categorical variables and t-tests for continuous variables, with a significance threshold of p < 0.05. Results: Participants had a mean Body Mass Index (BMI) of 30.33 ± 6.14 kg/m² and an average age of 32.65 ± 4.99 years; 54% of them were Qataris. Of the patients, 58.5% had positive thyroid antibodies and 55.7% had pre-gestational hypothyroidism. Women with pre-gestational hypothyroidism required significantly higher levothyroxine doses compared with those with gestational hypothyroidism (93.2 ± 47.5 mcg/day vs. 67.6 ± 30.1 mcg/day; p < 0.001). Treatment adjustment was demonstrated by the improvement in TSH normalization from 51.3% in the first trimester to 64.2% in the third trimester (p = 0.041). No significant associations were observed with pre-eclampsia, preterm delivery, hypertension, or placental abruption. However, women with normal third-trimester TSH had a higher prevalence of gestational diabetes mellitus (GDM) compared with those with elevated TSH (51.6% vs. 36.8%; p = 0.013). Conclusions: Appropriate trimester-specific monitoring and timely levothyroxine titration was associated with improved biochemical control without adverse maternal outcomes. Greater levothyroxine requirements in women with pre-gestational hypothyroidism emphasize the importance of early intervention. These findings highlight the potential benefit of structured thyroid monitoring and multidisciplinary care approaches in pregnancy and may help inform future regional clinical practice guidelines.