This descriptive cross sectional study was done for the estimation of thyroid hormone in early pregnancy and it's clinical correlation. It was conducted at the Antenatal Clinic of Mymensingh Medical College Hospital, Mymensingh from December 2010 to November 2011. Total 185 cases in early pregnancy were taken purposively and randomly. Among the pregnant women, age ranged from 18-42 years with the Mean±SD age 25.77±4.96 years, the gestational weeks ranged 6±1 to 13±1weeks having Mean±SD 9.06± 2.49 weeks. The gravida ranged from primi to 8th gravida Mean±SD 1.89±1.10. Haemoglobin level ranged from 9.0 to 13.2gm/dl; Mean±SD 10.90±0.99gm/dl. Mean±SD of serum FT4 was 17.77±7.25 and Mean±SD of TSH was 3.95±2.94mIU/L. In present study, 5.40% (n=10) of the respondents had hypothyroidism and 0.54% (n=1) showed hyperthyroidism. The present study showed that, the incidence of hypothyroidism had relatively increased then the reference ranges but not statistically significant. But hyperthyroidism was within the reference range. This study showed slightly higher percentage of hypothyroidism in both ≤30 (4.52%) and ≥30 (10%) years of age groups especially a bit higher percentage in the elderly group. In present study, hypothyroidism was common among women of lower income group. Present study showed a higher percentage of stillbirth &miscarriage among study population. This study showed a relatively higher prevalence of abnormal thyroid function (especially hypothyroidism) in the study population and suggests the routine screening of thyroid hormone in early pregnancy in addition to routine antenatal care.