Endometrial biopsy during a cycle of conception.

Endometrial biopsies obtained from 18 infertile women during early intrauterine pregnancy were examined histologically. The cycle date on which the biopsies were obtained was determined from the day of ovulation by basal body temperature charts and prior menstrual history. The average cycle dates of the biopsies were similar for the women who delivered at term or who had first-trimester spontaneous abortions.