“…From the mid-1960s, studies have been conducted to assess the pituitary effects of various progestogens. Doses of gestagens have been Znt J Gynecol Obstet 32 reported to suppress LH and FSH excretion [20,22,25,57]. Whereas combined oral contraceptives inhibited the ability of the pituitary to respond to LH-RH, there was no inhibition in women taking low doses of lynestrenol, norethisterone or norgestrel [ 161.…”