The pill works in several ways to prevent pregnancy. The pill suppresses ovulation so that an egg is not released from the ovaries, and changes the cervical mucus, causing it to become thicker and making it more difficult for sperm to swim into the womb. The pill also does not allow the lining of the womb to develop enough to receive and nurture a fertilized egg.
This method of birth control offers no protection against sexually-transmitted diseases.
Review Date 1/14/2018
Updated by: John D. Jacobson, MD, Professor of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda Center for Fertility, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.