What is emergency contraception?
Emergency contraception is a way to prevent pregnancy if:
- You had sex without using birth control. There is a chance that you could get pregnant even if you haven't started having periods yet or you are getting close to menopause.
- Your birth control method failed. Maybe you forgot to take your pill or get your shot. Or maybe the condom broke or came off, or your diaphragm slipped.
- You used a birth control method that isn't very reliable, or you didn't use it the right way.
- You were sexually assaulted. Even if you were using birth control, emergency contraception can help decrease your chance of getting pregnant.
Using emergency contraception right away can prevent an unwanted pregnancy. And it can keep you from worrying while you wait for your next period to start.
What are the types?
There are two main types of emergency contraception: pills and intrauterine devices (IUDs). Pills work well, don't cost a lot, and are usually easy to get. The IUD works very well, but it has to be inserted by a doctor.
- Pills used for emergency contraception are sometimes called "morning-after pills." They can be used up to 5 days after unprotected sex.
- The most common option contains a progestin hormone called levonorgestrel. Progestin is a synthetic version of the hormone progesterone.
- Another option is a medicine called ulipristal (for example, Ella). It affects the progesterone in your body.
- Some birth control pills are also used. These often contain a combination of the hormones estrogen and progestin. If you already take birth control pills, you may be able to use the pills you have as emergency contraception. Talk to your doctor to find out the correct doses.
- An IUD is a small, T-shaped plastic device that is inserted into your uterus. It can be placed up to 5 days after unprotected sex to prevent pregnancy.
- A copper IUD is a common option. Copper wire is wound around the stem of the T-shaped IUD. The copper IUD can stay in place for up to 10 years. Your doctor may talk to you about leaving it in for longer.
- A hormonal IUD can also be used. This type releases levonorgestrel, which is a form of the hormone progestin. The hormonal IUD used for emergency contraception can prevent pregnancy for 6 years. But your doctor may talk to you about leaving it in for longer.
How does it work?
Emergency contraception pills work by preventing ovulation, fertilization, or implantation.
The hormones in these pills may prevent fertilization by stopping the ovary from releasing an egg (ovum). They also make the fallopian tubes less likely to move an egg toward the uterus. The pills are also thought to thin the lining of the uterus, or endometrium. The thickened endometrium is where a fertilized egg would normally implant and grow.
An IUD for emergency contraception may prevent fertilization or implantation.
Where can you get emergency contraception?
Where you get emergency contraception may depend on which type you use.
You can get emergency contraception without a prescription at most drugstores.
Some types of emergency contraception, such as ulipristal acetate (for example, Ella) are available only from family planning clinics or with a prescription from a doctor.
Birth control pills
If you already have birth control pills on hand, you may be able to use them for emergency birth control. To find out which brands of pills work and how to take them, go to www.plannedparenthood.org or https://ec.princeton.edu for emergency contraception information.
You can get an IUD from many doctors, from college and public health clinics, and in most hospital emergency rooms. An IUD has to be inserted by a doctor or other health professional.
What to do if you can't find emergency contraception
Some pharmacists won't sell emergency contraception or fill prescriptions for birth control pills. If this happens to you, ask for the location of a pharmacist who will, or go to or call the Planned Parenthood clinic nearest you.
How to Use It
How you use emergency contraception depends on which type you use.
The pills come in 1-pill or 2-pill packages. Follow the directions in the package, or take them as your doctor directs you to.
You can take emergency contraception up to 5 days after unprotected sex.
Birth control pills as emergency contraception
For most regular birth control pills, you take one dose of 2 to 5 pills as soon as you can. Then you take a second dose 12 hours later. The dose depends on the type of pill.
If you use birth control pills for emergency contraception, keep these things in mind:
- Birth control pills can cause nausea. Take an antinausea medicine such as Dramamine with the first dose and again 1 hour before the second dose.
- If you vomit within 2 hours after you take the pills, call your doctor for advice. You may need to repeat the dose.
- Be sure you take the active hormone pills. In a 28-day pack, the first 21 pills contain hormones. The last 7 pills (the ones you take during your period) don't contain any hormones. If you use 21-day packs, all of the pills contain hormones.
A doctor or other health professional has to insert an IUD.
How Well It Works
The sooner you use emergency contraception, the more likely it is to prevent pregnancy. Overall:
- An IUD is the most effective form of emergency contraception. It is inserted by a doctor and can almost always prevent pregnancy.
- A prescription pill with ulipristal acetate (such as Ella) works better in most cases to prevent pregnancy than the pill with levonorgestrel. If you have used hormonal birth control in the last week or have been using the shot, the prescription pill may not work well for you.
- Emergency contraceptive pills may not be as effective. But they are available without a prescription at most drugstores.
If you are overweight, emergency contraception pills may not work as well to prevent a pregnancy. Talk with your doctor about methods that aren't affected by your weight, such as an IUD.
Your doctor may suggest that you have a pregnancy test about 3 weeks after using emergency contraception.
Emergency contraception is not a replacement for regular birth control
Unless you get an IUD, emergency contraception doesn't take the place of regular birth control. Find a good method of birth control you can use every time you have sex.
Emergency contraception pills won't protect you for the rest of your cycle. Use condoms or another barrier method of birth control until you start your period. If you usually use a hormonal method of birth control, such as birth control pills, the vaginal ring, or the patch, check with your doctor about when to start using them again.
But accidents can happen. It is a good idea to keep a set of emergency contraception pills on hand in case you ever need it.
Emergency contraception may cause some side effects.
- Emergency contraception pills may cause spotting or mild symptoms like those of birth control pills. It usually doesn't cause nausea.
- Birth control pills can cause nausea or vomiting. In some women, they can also cause sore breasts, fatigue, headache, belly pain, or dizziness.
- An IUD may cause cramping and bleeding during the first few days after it's inserted.
Call your doctor if you have a headache, dizziness, or belly pain that is severe or that lasts longer than 1 week.
If you are already pregnant, most pills won't harm the fetus. But some pills, such as ulipristal, may cause problems with the pregnancy. More research is needed to know for sure. An IUD could cause problems with the pregnancy.
Current as of: August 2, 2022
Author: Healthwise Staff
Sarah Marshall MD - Family Medicine
Kathleen Romito MD - Family Medicine
Adam Husney MD - Family Medicine
Elizabeth T. Russo MD - Internal Medicine