How birth control methods prevent pregnancyBirth control methods| Method | How it prevents pregnancy |
|---|
Hormonal | - 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
implantation should fertilization occur
| Intrauterine device (IUD) | - The progestin released by the
levonorgestrel (LNg) 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 | - 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 additional method or
abstinence should be used during this time of fertility.
| Permanent birth control (sterilization) | |
| |
