After ovulation, the endometrial histology should be secretory. Absence of secretory endometrium on a biopsy done late in the menstrual cycle suggests that ovulation did not occur or progesterone level is inadequate. Endometrial biopsy 10 to 14 days after a rise in basal body temperature or luteinizing hormone surge can be useful in an infertility evaluation. Even if conception has occured, a biopsy done 10 to 14 days after ovulation should not interfere with implantation. Endometrial biopsy should not be done more than 14 to 16 days after ovulation, since it may disrupt an early pregnancy (see contraindications).