Birth Control Pills

The hormones in birth control pills work by preventing ovulation.

Additionally, these hormones cause mucus in the cervix to thicken, making it difficult for sperm to enter the uterus, while, at the same time, they cause the uterus wall to become thinner, reducing the chances a fertilized egg will attach to it.

Typically, about 8 in 100 women (8%) will become pregnant during the first year birth control-pill use. Just 1 in 100 women who use the pill precisely as directed become pregnant the first year.

Besides contraception, other benefits of the combination birth control pill are:

  • Lighter and shorter periods, with less cramping.
  • Treatment of fibroids and endometriosis
  • May help rebalance hormones and prevent acne
  • Can reduce uterine and ovarian cancer risk and increase bone density during perimenopause.


Hormones: Substances produced by the body to control the functions of various organs. Ovulation: The release of an egg from one of the ovaries.
Cervix: The opening of the uterus at the top of the vagina.
Uterus: A muscular organ located in the female pelvis that contains and nourishes the developing fetus during pregnancy.
Fibroids: Benign growths that form in the muscle of the uterus.
Perimenopause: The period around menopause that usually extends from age 45 years to 55 years.