progestogens, with varying degrees of progestogenic activity, include 16?-hydroxyprogesterone (16?-OHP), 17?-hydroxyprogesterone (17?-OHP) (very weak), 20?-dihydroprogesterone (20?-DHP), 20?-dihydroprogesterone (20?-DHP), 5?-dihydroprogesterone (5?-DHP), 5?-dihydroprogesterone