THYROID-FUNCTION STUDIES IN NORMAL PREGNANT TANZANIAN WOMEN

Iodine deficiency is well known as a cause of several disorders such a s endemic goiter and cretinism, along with a wide spectrum of psychone urologic development disorders including endemic mental deficiency, wh ich are generally correlated with damage to the fetus. Since as much a s 40% of the Tanzanian population is at risk for iodine deficiency dis orders (IDD) because they live in iodine-deficient areas, and although the effects of iodine deficiency on human reproduction in Tanzania ha ve not been objectively studied, it is estimated that there are approx imately 600,000 cretins and cretinoids in the country as a result of I DD. As a baseline study for future research on iodine deficiency and i ts effects on human reproduction in Tanzania, we assayed serum thyroxi ne (T4), triiodothyronine (T3), thyrotropin (TSH), and free thyroxine (FT4) in 93 clinically euthyroid pregnant women and 34 nonpregnant wom en as controls. Pregnancy was accompanied by significantly increased l evels of total T3 and T4, decreased FT4, and increased TSH concentrati ons in serum. However, biochemical euthyroidism (assessed by FT4 and b asal TSH) was demonstrated in almost all (99%) of the pregnant subject s in conformity with most of the previous findings elsewhere. We concl ude that pregnant Tanzanian women residing in areas without iodine def iciency experience changes in biochemical parameters of thyroid functi on similar to their counterparts in other places.