In vitro fertilization: the degree of endometrial insufficiency varies with the type of ovarian stimulation.

Fifty-eight patients in an in vitro fertilization program who did not have embryo transfers had endometrial biopsies performed on the second day after ovulation. The patients had been stimulated with clomiphene citrate (CC) and human chorionic gonadotropin (hCG) (group I); with CC, human menopausal gonadotropin (hMG), and hCG (group II), or with hMG and hCG (group III). Only 17 patients (30%) showed a normal luteal phase histology. The remaining 41 patients (70%) showed variety of endometrial abnormalities. Patients stimulated with hMG and hCG (group III) had a normal luteal phase at a significantly higher rate (48% versus 16%). Women below the age of 35 had a significantly higher rate of normal luteal phase histology than women older than 35 years. The study establishes abnormal endometrial histology as a possible cause of the low pregnancy rate of in vitro fertilization. The degree of endometrial histologic abnormality varies considerably with the type of ovarian stimulation used.