Prevalence of hypothyroidism in pregnancy: An epidemiological study from 11 cities in 9 states of India

Background: A previous hospital based study from Delhi revealed a high prevalence of hypothyroidism in pregnant women. Several other studies with small sample size also indicate a rising trend of prevalence of hypothyroidism during pregnancy in India. Objective: To assess prevalence of hypothyroidism in pregnant women from various states/cities across India. Materials and Methods: This was a cross-sectional multicenter study conducted at Allahabad (Uttar Pradesh), Bengaluru (Karnataka), Chennai (Tamil Nadu), Kolkata (West Bengal), Hyderabad (Telangana), Nasik (Maharashtra), Rohtak (Haryana), Pune (Maharashtra), New Delhi (Delhi), Srinagar (Kashmir), and Vizag (Andhra Pradesh) enrolling 2599 pregnant women. Estimation of thyroid stimulating hormone (TSH), free T4, and antithyroid peroxidase (TPO) antibodies was carried out using Roche modular kit using ECLIA technology in a central laboratory. Results: We found in our study population that 13.13% of pregnant women have hypothyroidism (n = 388), using a cutoff TSH level of 4.5 μIU/ml. This prevalence was much higher using the American Thyroid Association criteria. Anti-TPO antibodies were positive in 20.74% of all pregnant women (n = 613), whereas 40% (n = 155) of hypothyroid pregnant women were positive for anti-TPO antibodies. Conclusion: This study concludes that there is a high prevalence of hypothyroidism (13.13%), majority being subclinical in pregnant women during the first trimester from India and universal screening of hypothyroidism may be desirable in our country.