Measurement of plasma human chorionic gonadotropin (hCG) and beta-hCG activities in the late luteal phase: evidence of the occurrence of spontaneous menstrual abortions in infertile women.

Plasma luteinizing hormone (LH-human chorionic gonadotropin (hCG) and beta-hCG activities were measured during the late luteal phase in 321 cycles of 147 infertile women. In 71 cycles the hCG measurement permitted the diagnosis of pregnancy between the 10th and 14th days after the thermal nadir. The slope of the regression line derived from hCG levels during the first 22 days of pregnancy was significantly lower in pregnancies which aborted before the 60th day than in normal pregnancies (P less than 0.01). Among 72 cycles ended by apparently normal menses which exhibited an LH-hCG activity at least equal to 7 mIU of hCG/ml during the late luteal phase, the beta-hCG activity was measured in 49 cycles during which hCG had not been given. Significant beta-hCG activity (greater than or equal to 4 mIU of hCG/ml) was detected in 19 cases. This finding supports the assumption that secretory trophoblastic tissue had been present and that spontaneous menstrual abortions had occurred in these women.