Abstract

Overview: Hypothyroid is a common endocrine disoder in pregnancy. Thyroid hormon is critical to normal development of the fetal’s brain and nervous system. During the first trimester, the fetus depends on the mother’s supply of thyroid hormone. Objectvies: to assessment changing thyroid hormone dose during the first trimester of pregnancy in women with primary hypothyroid being treated thyroxine. Method: Observe and follow up to 14 th week of pregnancy on 83 women with primary hypothyroid being treated thyroxine. Assesst thyroxine dose at 3 antenatal appointment: 6 th week, 10 th week and 14 th week of pregnancy. Result: Thyroxine dose was increased after the first antenatal appointment (61,3%). The median of thyroxin dose was 76,59 µg/day prepregnancy; 95,27 µg after the first, 100,4 µg/day, 101,9 µg/day after the 2 th and 3 th appointment. Median increased was 60,71 µg/day in congenital hypothyroid group. Conclusion: The vast majority of primary hypothyroid-treated women who achieve pregnancy need an increase in the thyroxine dose during the first trimester. This requirement tends to occur before 6 th week of pregnancy