An Evaluation of Thyroperoxidase Antibody in Antenatal Mothers with Hypothyroidism to Assess the Prevalence of Autoimmune Thyroiditis in Perambalur District, Tamil Nadu

Background: Hypothyroidism during pregnancy poses significant risks to maternal and fetal health, with autoimmune thyroiditis (Hashimoto's thyroiditis) being a leading cause in iodine-sufficient regions. Thyroperoxidase (TPO) antibodies serve as a key marker for autoimmune thyroid disease. This study aimed to evaluate the prevalence of TPO antibody positivity in hypothyroid antenatal women in Perambalur district, Tamil Nadu, India. Methods: A cross-sectional observational study was conducted from July 2017 to July 2018 at Dhanalakshmi Srinivasan Medical College and Hospital. Eighty antenatal women aged 18-30 years with newly diagnosed hypothyroidism (TSH >10 μIU/mL) were included. Serum levels of total T3 (TT3), total T4 (TT4), thyroidstimulating hormone (TSH), and TPO antibodies were measured using enzyme-linked immunosorbent assay (ELISA). Participants were categorized into TPO-positive (≥50 IU/mL) and TPO-negative groups. Demographic data, thyroid profiles, and correlations were analyzed using descriptive statistics and Pearson's correlation. Results: Of the 80 participants, 47 (58.75%) were TPO-positive. The mean age was 25.55 ± 5.09 years in the TPO-positive group and 26.03 ± 4.87 years in the TPO-negative group (p > 0.05). TPO-positive women had significantly higher TSH (22.68 ± 6.15 μIU/mL vs. 17 ± 4.4 μIU/mL; p < 0.01) and lower TT3 (0.6 ± 0.2 ng/mL vs. 0.8 ± 0.4 ng/mL; p < 0.01) and TT4 (2.9 ± 1 μg/dL vs. 3.3 ± 1.2 μg/dL; p < 0.01). A strong positive correlation was observed between TPO antibodies and TSH (r = 0.7, R² = 0.49; p < 0.01). TPO-positive women had higher rates of family history of thyroid dysfunction (40% vs. 33%) and past miscarriages (25.5% vs. 18%; p < 0.01 for miscarriages). Conclusion: The prevalence of Hashimoto's thyroiditis in hypothyroid antenatal women in this region is high (58.75%), underscoring the need for routine TPO antibody screening in early pregnancy to mitigate adverse outcomes. Universal screening and early intervention could improve maternal and fetal health.