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 mIU/L during the first trimester was considered to be normal. RESULTS The TSH levels ranged from 0.04 to 13.3 mIU/L (median 1.73 mIU/L, mean 1.88 mIU/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.