The main function of mammalian corpus luteum is to produce

The ovulation (ovulatory phase) is followed by the luteal phase during which the remaining parts of the Graafian follicle transform as the corpus luteum. The corpus luteum secretes large amounts of progesterone which is essential for maintenance of the endometrium. Such an endometrium is necessary for implantation of the fertilized ovum and other events of pregnancy. If fertilization and implantation do occur, the corpus luteum is maintained by hCG which is secreted by placenta. The corpus luteum secretes progesterone, estrogens, relaxin, and inhibin.