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How Birth Control Methods Prevent Pregnancy - Topic Overview

Birth control methods
Method How it prevents pregnancy

Hormonal camera.gif

  • Prevents ovulation
  • Thickens mucus at the cervix so sperm cannot pass through
  • Changes the environment of the uterus and fallopian tubes to prevent fertilization and to prevent implantation if fertilization occurs

Intrauterine device (IUD) camera.gif

  • The progestin released by the hormonal IUD prevents fertilization by making the mucus in the cervix thick and sticky, so sperm can't get through to the uterus. The progestin and IUD change the uterine lining, preventing implantation in the rare case that fertilization occurs.
  • The copper in the copper IUD is toxic to sperm. It causes changes in the uterus and fallopian tubes that kill sperm. The IUD changes the uterine lining, which prevents implantation in the rare case that fertilization occurs.

Barrier methods camera.gif

  • Block sperm from reaching the egg
  • Some are used with spermicides, which kill sperm.

Fertility awareness (natural family planning)

  • Identifies the time during a woman's cycle when she is most likely to become pregnant (fertile). An extra method or abstinence should be used during this time of fertility.

Permanent birth control (sterilization)

    This information is produced and provided by the National Cancer Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National Cancer Institute via the Internet web site at http:// cancer .gov or call 1-800-4-CANCER.

    WebMD Medical Reference from Healthwise

    Last Updated: May 03, 2012
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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