a) Oestrogen or Progesterone b) FSH stimulates follicles in the ovaries to mature while progesterone has a "maintenance" function as it maintains the lining of the uterus. Progesterone also has an inhibitory effect on FSH- inhibiting its secretion. By the female taking progesterone supplements and increasing the concentration of progesterone in her body, FSH secretion will be inhibited and therefore the follicles will not be stimulated to mature therefore there will be no release of the ovum.