Abstract : Among all Maternal medical disorders, hypothyroidism is the major causative factor. The estimated prevalence of subclinical hypothyroidism (SCH) in pregnancy has been reported as 2.3% which is significantly higher than the prevalence of overt hypothyroidism in pregnancy considering the cut off value of TSH as 2.5 IU/ml. Few studies about effect of increased TSH levels on miscarriage and still birth are available from India. The present study was undertaken to test whether SCH is associated with early trimester miscarriage and unexplained stillbirths in our Indian population as it is an easily preventable incident with early installation of thyroid replacement therapy. Using an observational, cross sectional study model, thyroid stimulating hormone (TSH) and free thyroxine (FT4) were assayed in serum by ELISA method from 250 pregnant women having miscarriages within 12 weeks during a study period of one year. Results: In spite of having no significant difference in the fT4 values between the patients with and without miscarriage the serum TSH levels were significantly raised in patients having miscarriage as evident from both independent t test (mean ± SD: 3.5 ± 2.2 vs 2.80 ± 1.5) and Mann Whitney test (median: 2.87 vs 2.44). Results of correlation study showed that there was a significant association between the serum TSH levels and number of miscarriages (r = 0.246, P < 0.001) without any such relationship with the thyroxine values (r = -0.01, P = 0.06). We conclude that even if thyroxin levels appear to be normal in compensated hypothyroid pregnant women, raised values of TSH impose risk of miscarriage. So, we recommend that in spite of having a normal fT4 value serum TSH should be monitored within their trimester specific normal values to prevent early miscarriage.