ABSTRACT
Since at early pregnancy [<20 week] fetal thyroid gland is undeveloped, normal development of the Fetal brain is highly dependent on maternal thyroid hormones. There are excessive adverse perinatal outcomes associated with overt and subclinical hypothyroidism such as increase of Abortion, preeclampsia, placenta Abruption, LBW, preterm labor, impaired fetal neuropsychological development and low IQ scores. The aim of this study was to determine the prevalence of hypothyroidism and its relationship with some known risk factors among pregnant women with gestational age<20 wk. A total of 620 pregnant women referred to Dadbin clinic [Kerman/Iran] for their first prenatal care before the 20th week of gestational age were studied for TSH and FT4 levels by Elexis method. A questionnaire including known risk factors of hypothyroidism was filled out for each participant. The prevalence of both clinical and subclinical hypothyroidism and its probable association with some risk factors were studied. The prevalence of hypothyroidism was 10.15% [clinical=2.25% and subclinical=7.9%]. Except for allergy, no relationship between hypothyroidism and considered risk factors was found. Due to the high prevalence of hypothyroidism [clinical and subclinical] and its neonatal and maternal outcomes, hypothyroidism screening in all pregnant women as one of the routine prenatal cares is suggested