Emergency contraception, also known as the “morning-after pill,” is a type of contraception (birth control) that can work up to 5 days (or 120 hours) after unprotected sex or contraception failure (such as a condom breaking) to prevent a pregnancy before it starts. Emergency contraception does not cause abortion and is not the same thing as abortion medication.
There are 4 emergency contraceptive methods available: 2 pills and 2 IUD options.
Pill options
Emergency contraception pills like levonorgestrel-based pills and Ella prevent pregnancy in several ways. It works mainly by preventing ovulation (when the ovary releases an egg) and thickens cervical mucus so sperm cannot reach an egg. Taking either of these does not protect you from sexually transmitted infections (STIs) or another possible pregnancy if you have unprotected sex again.
Emergency contraception pills are only recommended as a backup and should not be used as a primary method of birth control.
IUD options
Hormonal and Copper IUDs are the most effective emergency contraceptive option if inserted within 5 days of unprotected sex. Learn more by visiting our IUD page.
More information
Emergency contraception is most effective when taken as soon as possible after unprotected sex or contraception failure. The number of people who will become pregnant after using emergency contraception:
- Plan B (levonorgestrel-based pills): 15-26 out of 1,000 people
- Ella (ulipristal acetate): 12-18 out of 1,000 people
- Hormonal IUD: 3 out of 1,000 people
- Copper IUD: 1 out of 1,000 people.
There are no serious long-term side effects of using emergency contraception. In the short-term, it can cause:
- Plan B and Ella: nausea, vomiting, earlier or later menstruation (periods), heavier or irregular bleeding, or spotting
- Hormonal IUD: pain or discomfort with IUD placement, cramping after placement, breast tenderness, mood changes, irregular bleeding or spotting
- Copper IUD: pain or discomfort with IUD placement, cramping after placement, increased menstrual cramping, irregular bleeding or spotting.
To learn more about the birth control methods available, visit our Family Planning and Birth Control page.
For more information about emergency contraception:
https://www.bedsider.org/birth-control/emergency_contraception#submenu
https://www.your-life.com/en/contraception-methods/other-methods/emergency-contraceptives
A quick note about emergency contraceptives and body weight: Some research has found that levonorgestrel (Plan B) is less effective for those who weigh more than 165 pounds or have a BMI of 25 or more (calculate your BMI here). Because the data isn’t clear, the FDA does not believe a change in labeling to exclude the use of Plan B in any person, regardless of how much they weigh, is needed at this time.
Other options for emergency contraceptives for those with larger bodies include ulipristal acetate (Ella) or a copper or hormonal IUD. Ella may not be as effective if the patient’s BMI is 35 or more, but the copper and hormonal IUDs do not seem to be affected by weight.