Detection of chorionic gonadotrophin like activity in infertile cycles with a short luteal phase.

Three of 24 infertile women with a short luteal phase transiently showed chorionic gonadotrophin (HCG) like immunoreactivity in serum as measured by the HCG-beta subunit radioimmunoassay. The plasma progesterone concentration was elevated above the lower normal postovulatory level in 2 of these women who also had elevated basal body temperature at the time HCG was detected. Positive HCG reaction coincided with the pre-ovulatory surge of luteinizing hormone (LH) in one patient, but in 2 other cases the LH concentration was low suggesting absence of LH interference. Our results suggest that some infertile women may conceive during their cycles with a short luteal phase and maintain pregnancy until HCG becomes detectable.