What happens during the luteal phase?
Well the newly formed corpus luteum produces progesterone which transforms the proliferative endometrium into the secretory endometrium in preparation to the implantation of the embryo. The appropriate secretions of the secretory endometroium is important for the normal implant ion of the embryo. In the non-fertile enstrual cycle, the CL produces progesterone for 2 weeks and then regresses. As it undergoes luetolysis its production of progesterone declines and the circulating levels of progesterone along with estrogen and inhibin (the other hormones that the corpus luteum secretes) decline. The loss of progesterone support to the endometrium causes destabilization of th elands and stroma and rsults in sloughing off go the endometrium during menstruation. The decrease int he progesterone, estrogen, inhibin also removes the negative feedback at the levels of the hypothalamus and pituitary and circulating FSH levels increase with the start of the next cycle.