Corpus luteum involution

LH secretion which induces rupture of the follicle and release of the mature egg into the fallopian tube. In the ovary a corpus luteum forms, which secretes progesterone (maximal at about day 21) to prepare the endometrium for implantation of an early embryo. If pregnancy does not occur, the corpus luteum involutes, progesterone levels fall, and the thickened endometrium is shed giving rise to menstrual bleeding, which is defined as starting on day 1 of the next cycle. 

If fertilization does not occur, the corpus luteum involutes, the progesterone and oestradiol levels fall and the endometrium breaks down with menstruation resulting. 

FUNCTION Prevents corpus luteum from involuting in pregnancy, allowing a rise of estrogen and progesterone. 

In childbearing age during each menstrual cycle a number of follicles are stimulated to begin to mature, but usually only a single follicle completes the process. At mid-cycle the preovulatory dominant follicle can be identified as a thin-waUed cyst attaining a size of approximately 15-25 mm [7]. After formation of the corpus luteum the wall may involute and become irregular. Corpus lutea maybe cystic or involuted and noncystic [3]. Furthermore,... 

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