Progesterone inhibits FSH and LH and so remains high during pregnancy. Days 1 to 12 – oestrogen gradually increases and peaks approximately on the 12th day. Progesterone, LH and FSH stay ...

Low levels of progesterone and estrogen cause the hypothalamus to send a releasing hormone (GnRH) to the pituitary gland. The releasing hormone signals the pituitary gland to release FSH (follicle ...