How many days before a period does ovulation stop?

Ovulation does not stop before a period. Ovulation occurs when a mature egg is released from one of the ovaries, usually 14 days before the start of a woman's menstrual period. After ovulation, the corpus luteum, a temporary gland that forms on the ovary, produces hormones that help to thicken the lining of the uterus in preparation for pregnancy. If pregnancy does not occur, the corpus luteum breaks down and the levels of these hormones decrease, which causes the lining of the uterus to shed and a menstrual period to begin.