Endometrial biopsy: a test whose time has come and gone.

To document ovulation in an infertility investigation, a timed endometrial biopsy is painful, expensive, invasive, requires precise cycle timing for proper interpretation, and cannot independently distinguish between fertile and infertile women. Urinary LH kit testing has a significant false-positive rate (approximately 7.6%). A midluteal serum progesterone is a much simpler method that compares favorably with either endometrial biopsy or LH kit testing.