comparison of thyroid hormone levels between normal and preeclamptic pregnancies

background: to investigate thyroid function in preeclamptic patients in comparison with normal pregnant women. methods: in this analytical cross-sectional study free thyroxine (t4), and thyroid stimulating hormone (tsh) levels were measured in 100 preeclamptic patients and were compared with free t4 and tsh levels in 101 normal pregnant women in their third trimester of pregnancy. patients with thyroid or other systemic disorders were excluded from this study. results: a significant difference in concentration of free t4 levels (0.729 ±0.324 ng/ dl versus 0.929± 0.314 ng/dl, p < 0.001) was observed in the preeclamptic group compared with the normotensive group, but the mean tsh level was not significantly different (2.935±1.16 miu/l versus 2.339±1/15 miu/l, p = 0.170). conclusion: women who develop preeclampsia are more likely to have lower normal limits of thyroid function during their final weeks of pregnancy.