Point Prevalence of Abnormal Thyroid-Stimulating Hormone during the First Trimester of Pregnancy in Israel

Background: The prevalence of thyroid dysfunction in early pregnancy in Israel is not known. Objectives: To assess the rate of abnormal thyroid-stimulating hormone (TSH) tests in low risk pregnant women attending a community clinic in Israel. Methods: We conducted a retrospective analysis of the charts of low risk pregnant women (n=303) who had undergone a TSH screening during the first trimester of pregnancy at Clalit Health Services Women's Health Centers in Ashkelon and Tel Aviv. TSH of 0.1-2.5 mlU/L during the first trimester was considered to be normal. Results: The TSH levels ranged from 004 to 13.3 mlU/L (median 1.73 mlU/L, mean 1.88 mlU/L). The rate of abnormal TSH was 25.6%, with low TSH 2.3% and high TSH 23.4%. The prevalence of abnormal TSH was not influenced by gravidity (primigravidas versus multigravidas) or:place of residence Ashkelon or Tel Aviv). Conclusions: In view of the high prevalence of abnormal TSH (25.6%) in pregnant women in Israel during the first trimester, a universal country-wide screening should be considered.