What will be the interplay of hormones during bleeding phase of menstrual cycle if unfertilized secondary oocyte undergoes autolysis?

Progesterone and estrogen continue the hypertrophy of endometrial lining. Progesterone inhibits the release of LH from pituitary causing regression of Corpus luteum. Prolactin and progesterone reduces LH level causing regression of Corpus luteum. Prolactin and estrogen inhibits progesterone secretion leading to sloughing off uterine lining .

Progesterone inhibits the release of LH from pituitary causing regression of Corpus luteum.

If the ovum is not fertilized then the progesterone inhibits the release of LH from pituitary causing regression of Corpus luteum and leading to the bleeding which usually lasts for about 3-5 days.