Thyroid Function In Pregnant Women With Hyperemesis

We conducted a longitudinal study of serum levels of Thyroid stimulating hormone (TSH) and free thyroxine (FT4) in 22 normal pregnant women and 31 patients with hyperemesis gravidarum. When compared with the values in non-pregnant women, the mean serum FT4 level in the normal pregnant women was decreased significantly in the second and third trimesters (P<0.001), while their mean serum TSH level was significantly increased in the second (P<0.05) and third (P<0.001) trimesters. The group of patients with hyperemesishad a significantly higher mean serum FT4 in the first (P<0.001) and second (P<0.05) trimesters, and a lower mean serum TSH (P<0.001) in the first trimester when compared to a group of normal pregnant women matched for stage of gestation. Serum TSH was suppressed in 80% of patients with hyperemesis. Notably, at 20.9 + 3.6 weeks gestation, serum TSH and FT4 levels had returned to normal in 95% of patients with hyperemesis. Results of tests of thyroid function in women with hyperemesis gravidarum should be interpreted cautiously.