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How Birth Control Methods Prevent Pregnancy

Overview

The following table lists the different types of birth control methods and how they work to help prevent pregnancy.

How birth control methods prevent pregnancy

Method

How it prevents pregnancy

Hormonal

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

Intrauterine device (IUD)

  • There are two types of IUDs (hormonal and copper). Both types may work by preventing:
    • Fertilization of the egg.
    • Implantation in the uterus.

Barrier methods

  • Block sperm from reaching the egg.
  • Some are used with spermicide, which kills 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)

  • Men: Vasectomy blocks the release of sperm.
  • Women: Tubal ligation surgery or tubal implants block the movement of an egg through the fallopian tube and prevent fertilization.

Related Information

Credits

Current as of: November 22, 2021

Author: Healthwise Staff
Medical Review:
Sarah Marshall MD - Family Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
Elizabeth T. Russo MD - Internal Medicine
Femi Olatunbosun MB, FRCSC - Obstetrics and Gynecology