Actions of mifepristone (RU-486) include:
a) Inhibition of ovulation during the follicular phase by blocking hypothalamic-pituitary progesterone receptors, which suppresses midcycle gonadotropin release
b) During the luteal phase, inhibition of progesterone action on the uterus, which induces prostaglandin release from the endometrium
c) Termination of pregnancy by facilitating luteolysis, menstruation, uterine motility, softening of the cervix, and detachment of the embryo.
d) All of the above