Recurrent pregnancy loss and thyroid abnormalities: a case control study from a tertiary care hospital in Delhi

Background: To evaluate the association of thyroid dysfunction and thyroid autoimmunity with recurrent pregnancy loss (RPL) and to assess their impact on pregnancy outcomes. Methods: This hospital-based case–control study was conducted at a tertiary care centre. Fifty-nine pregnant women with a history of two or more consecutive pregnancy losses were enrolled as cases and compared with 59 age-matched pregnant women with no prior pregnancy loss. Thyroid function tests and anti–thyroid peroxidase (anti-TPO) antibodies were assessed in all participants. Pregnancy outcomes were followed until delivery. Results: Thyroid dysfunction was significantly more prevalent among women with RPL compared to controls (35.6% vs. 18.6%, p=0.03). Subclinical hypothyroidism was the most common abnormality, observed in 25.4% of cases and 13.6% of controls. Anti-TPO antibody positivity was higher among cases than controls (20.3% vs. 13.6%), though this difference was not statistically significant. Increasing severity of thyroid dysfunction was significantly associated with a higher number of pregnancy losses (p=0.004). Among women with RPL, those with thyroid dysfunction had lower live birth rates compared to euthyroid women (61.9% vs. 81.6%, p=0.04), along with higher rates of miscarriage and neonatal intensive care unit admission. Conclusions: Thyroid dysfunction, particularly subclinical hypothyroidism, is more common in women with recurrent pregnancy loss and is associated with adverse pregnancy outcomes. Routine screening for thyroid dysfunction and thyroid autoimmunity should be considered in the evaluation of women with RPL.