Endocrine Abstracts

Introduction: Maternal thyroid deficiency can induce serious adverse events on both mother and fetus during the whole period of pregnancy. The purpose of this study was to determine various epidemiological aspects of thyroid dysfunction among persian pregnant women.

Methods: Four hundred-eighty pregnant women with a mean age of 26.9±5 regardless of their gestational age were registered. After recording their medical history, serum samples were collected to measure thyrotropin (TSH), free thyroxine (FT₄) and thyroid auto-antibodies (anti-TPO and anti-Tg). Thyroid dysfunction was defined by the trimester-specific reference intervals for TSH and FT₄.

Results: The prevalence of elevated and depressed TSH for gestational age was 19.4 and 1% respectively. Overall anti-TPO antibody were detected in 31 (6.4%) women, and 12 (12.8%) women with high TSH were anti-TPO positive. Subclinical hypothyroidism was observed in 82 (17.1%) during all trimester while the prevalence of overt hypothyroidism and isolated hypothyroxinemia were 2.5 and 8.7% respectively. The prevalence of subclinical hypothyroidism in the first, second and third trimesters were 13.4, 20.7 and 65.8% respectively. Regarding thyroid auto-antibodies 12 (14.4%) women with subclinical hypothyroidism were ATPO positive while 7 (8.4%) of them had both ATPO and TG antibody positive.

Conclusion: The Persian pregnant women studied here, had much higher prevalence of subclinical hypothyroidism and overt hypothyroidism compared to western population (17 vs 2.5–6% and 2.5 vs 0.5% respectively). The causes for the higher prevalence estimates should be investigated and clarified.