Corpus luteum is a yellowish mass of follicular cells that functions as a temporary endocrine structure under the action of the LH hormone which stimulates the corpus luteum to secrete less estrogen and more progesterone.
Corpus luteum secretes a large amount of progesterone which is essential for the maintenance of the endometrial thickness which is formed by estrogen.
Estrogen and progesterone inhibit the release of FSH, LH and GnRH. This prevents the development of new follicles during the luteal phase. Luteal phase lasts for 14 days. During this phase, the level of estrogen and progesterone will rise, while FSH and LH level drop. Low level of LH causes, degeneration of corpus luteum (corpus albicans) leading to a sudden decline in progesterone level that causes menstruation. In the absence of fertilization, the corpus luteum degenerate; the level of progesterone hormone will fall. This causes disintegration of the endometrium leading to menstruation, marking a new cycle.