Combined oral contraceptive pills act mainly by:

Ans: a (Inhibition of ovulation) Ref: Park, 19th ed, p. 398Mechanism of action of combined OCPs is to prevent release of the ovum from the ovary. This is achieved by blocking the pituitary secretion of gonadotrophins that is necessary for ovulation to occur.Progestrone only pill - Renders the cervical mucus thick and scanty and thereby inhibit sperm penetration.Progesterone also inhibit tubal motility and will not increase it and it will delay the transport of the sperm and the ovum to the uterine cavity.