Menstrual cycle is regulated by hypothalamus through the pituitary gland. At the end of menstrual phase, the pituitary FSH gradually increases resulting in follicular development within the ovaries. As thefollicles mature, Estrogen secretion increases resulting in a surge in(FSH and LH) The surge of LH15 responsible for ovulation. LH also gonadotropins induces luteinisation. This leading to the formation of corpus luteum. Corpus luteum secretes progesterone and source estrogen which helps in maintaining the endometrium for implantation.