Objective: Estimate the proportion of subclinical/Overt hypothyroidism at 6 weeks post-partum in women diagnosed with subclinical hypothyroidism during current pregnancy and its association with anti-thyroid antibodies. Secondary objective is to estimate the proportion of congenital hypothyroidism in these babies. Design: Prospective Cohort study Setting: Department of Obstetrics and Gynecology, Jawaharlal Institute of Postgraduate Medical Education and Research, Tertiary care hospital, Puducherry, India. Population: Pregnant women >18years, diagnosed with subclinical hypothyroidism (SCH)during current pregnancy at 14-28 weeks of gestation. Methods: TSH, FT3, FT4, Anti-Thyroid peroxidase antibody & Anti-thyroglobulin antibodies were assessed antenatally and postnatally at six weeks. Neonatal TSH on day-3 were done. Main outcome measures: Proportion of persisting Subclinical hypothyroidism and congenital hypothyroidism. Association of antithyroid antibodies with postnatal subclinical hypothyroidism. Results: 156 participants were included, 15.3% had persisting SCH at six weeks postpartum. There was no significant association between Anti Thyroid antibodies with the persistence of SCH in the postnatal period. However, the percentage of subjects with anti-thyroid antibody positivity in the antenatal period was 23.7 %; it increased by 7.1 % in the postnatal follow-up (p=0.001). Congenital hypothyroidism was detected in 2% of cases. Conclusions: At six weeks postpartum, 15.3% of women had persisting SCH, emphasizing the need for routine postnatal screening. Long-time follow up studies are required for establishing its association with Anti-thyroid antibodies. The higher incidence of congenital hypothyroidism (2%) highlights the need for neonatal thyroid screening. Funding: Nil Keywords: Subclinical hypothyroidism, postpartum thyroid function, anti-thyroid antibodies, gestational hypothyroidism.