Thyroid function in the first trimester of pregnancy

Introduction - Dysthyroidism represents the second most frequent pathologies after diabetes in pregnant women. The thyroid undergoes many physiological changes during pregnancy and its functional activity increases by 50%. Thyroid hormones play an important role in the early stages of brain development. During the first trimester, the fetus is dependent on the production of maternal thyroid hormones. It is therefore important todetect, type and possibly treat any thyroid abnormality at the start of pregnancy; ideally,of course, taking care of these pathologies before conception.Patients and methods - we studied the variations in the plasma concentrations of the parameters of the thyroid balance, namely the thyroid stimulating hormone (TSH), the free thyroxine (fT4) and the free tri-iodothyronine (fT3) in fifty pregnant women in the 1st trimester of pregnancy.Results - Among the fifty pregnant women in the 1st trimester concerned by our study, 11 were in the 1st month, 19 in the 2nd and 20 in the 3rd month of pregnancy. The average age of our pregnant women was 30 ± 6.76 years with extremes ranging from 17 to 45 years old. The TSH assay revealed an average value in our pregnant women of 2.37 ± 4.01 mUI/Lwith extremes ranging from 0.031 to 26.37 mUI/L. The prevalence of hypothyroidism in our series was 8%. The other two parameters of the thyroid balance (fT3, fT4) showed an increase in their concentrations in the first month and then stabilization in the 2nd and 3rd month of pregnancy.Conclusion - Dysthyroidism is frequent in our study population, it must be systematically sought in any pregnant woman and properly managed in order to prevent complications both maternal and fetal.