The luteal phase defect.

In summary, the luteal phase defect is a deficiency of corpus luteum progesterone steroidogenesis, either in amount or duration, or both. The clinical manifestations include either primary infertility or repeated first trimester abortions. The diagnosis can only be made clinically on the basis of a well-timed endometrial biopsy that is read histologically as 2 or more days out of phase with the next period in at least two cycles.