FSH or follicle stimulating hormone secreted by the pituitary stimulates the growth of the ovarian follicles. It also helps in maturation and release of ovum like the LH or the leutinising hormone. Estrogen stimulates the thickening of the endometrial lining in anticipation of fertilisation and implantation. Progesterone aids in the implantation of the embryo into the uterine lining.