Most Birth-Control Pills Contain Both Progestin (Biologically Similar to Progesterone)

question 192

Multiple Choice

Most birth-control pills contain both progestin (biologically similar to progesterone) and estrogen. By taking a pill over consecutive days the amount of each hormone is maintained at a constant concentration in the circulating blood, inhibiting ovulation. Based on this information, what is the MOST likely mechanism for how birth-control pills affect ovulation?

• A)They inhibit growth of the uterine lining so implantation cannot occur.
• B)They inhibit growth of follicles so that immature eggs will be released.
• C)They inhibit maintenance of the corpus luteum after ovulation.
• D)They inhibit the release of the egg so that ovulation does not occur.