Study on thyroid function and thyroid autoantibody status in pregnancy considering the trimester specific range, is scarce in Bangladesh. This cross sectional study done in Bangabandhu Sheikh Mujib Medical University, Bangladesh from August 2012 to June 2013 encompassed 186 pregnant women of first trimester for study of thyroid function (TSH, FT₄) and anti-thyroid antibodies (anti-TPO, anti-TG). Age of the subjects was 25.4±4.9 years (mean±SD), median gestational age was 9 weeks. Applying the trimester-specific normal reference range set by American Thyroid Association (ATA), 48(25.8%) of the women were found to have thyroid dysfunction; 40(21.5%) subclinical hypothyroid (SCH), 1(0.5%) overt hypothyroid (OH) and 7(3.8%) hyperthyroid; 40(21.5%) women had goiter. If non-pregnant adult normal rage is used, 22 of SCH women as per ATA criteria will be labeled as normal and 19 normal women as per ATA cut off will be labeled as hyperthyroid. There was statistically significant disparity for functional status defined by these two references cut off value (p0.001). 29(15.6%) women had thyroid autoimmunity and the autoantibody positivity was more frequent in women with thyroid dysfunction than euthyroid women (22.92% vs. 13.04%, p0.001). Even though universal screening for thyroid dysfunction is not yet a recommendation, it should be considered in our population.
