Emergency contraceptive pill (Plan B)
Emergency contraception should only be used as emergency protection to prevent pregnancy.
What is the emergency contraceptive pill?
The emergency contraceptive pill (ECP) can be used to prevent pregnancy if taken within 72 hours (3 days) of having unprotected sex or an accident (for example, a broken condom). It is a form of emergency birth control and is also known as Plan B or the morning after pill.
How does emergency contraception work?
It works by doing one of 3 things:
- temporarily stops the release of an egg from the ovary
- prevents the egg from being fertilized by sperm
- prevents an egg that was fertilized by sperm from attaching itself to the uterus
How well does emergency contraception work?
Emergency contraception prevents roughly 95% of pregnancies if used within 24 hours of having unprotected sex. The effectiveness drops every 12 hours. If you need emergency contraception, it’s important to see a health care professional and start the medication as soon as possible. Plan B is less effective in women weighing 165 to 176 pounds and is not effective in women over 176 pounds. Women who weigh 165 pounds or more should speak to their health care provider.
What are the possible side effects of using emergency contraception?
- nausea
- vomiting
- breast tenderness
- blood spotting
- lower abdominal pain
- headaches
- dizziness
- diarrhea
- fatigue
Emergency contraception will not:
- end a pregnancy from earlier sexual contact
- cause an abortion
- protect you from becoming pregnant for the rest of the month
- protect you from sexually transmitted infections (STIs)
Where can I get emergency contraception?
Emergency contraception can be prescribed and administered by:
- your health care provider
- Public Health Sudbury & Districts’ Sexual Health Clinic
- a walk-in-clinic
This item was last modified on July 30, 2021