HCT and thyroid function in molar pregnancy.

HCT, TSH, T3, T4, PBI, T3-RSU, TBG binding capacity, BMR and thyroid uptake of radioiodine were measured simultaneously on the volunteers with hydatidiform mole and normal pregnancy. TRH stimulation tests were performed on the two groups. The serum HCT levels were higher in association with molar pregnancy than in normal pregnancy. TSH levels were within the nonpregnant range in the two groups. T3, T4, PBI, ETR, BMR and thyroid uptake of radioiodine suggested thyroid hyperfunction in molar pregnancy with a greater degree than that in normal pregnancy. TBG binding capacity and T3-RSU were similar in two groups. The peak TSH levels of TRH stimulation tests ranged widely in patients with molar pregnancies but were within the nonpregnant range in the subjects with normal pregnancies. These findings suggest thyroid hyperfunction in the molar pregnancy is due to a larger amount of HCT than in normal pregnancy.