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Our Health Library information does not replace the advice of a doctor. Please be advised that this information is made available to assist our patients to learn more about their health. Our providers may not see and/or treat all topics found herein. Emergency contraception is a way to prevent pregnancy if: 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. 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. 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 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. 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. 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 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. 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: A doctor or other health professional has to insert an IUD. The sooner you use emergency contraception, the more likely it is to prevent pregnancy. Overall: 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. 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. 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: November 27, 2023 Author: Healthwise Staff Current as of: November 27, 2023 Author: Healthwise Staff Clinical Review Board This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use and Privacy Policy. Learn how we develop our content. To learn more about Healthwise, visit Healthwise.org. © 1995-2024 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.Topic Contents
Emergency Contraception
Condition Basics
What is emergency
contraception?
What are the
types?
How does it
work?
Where can you get
emergency contraception?
Emergency contraception
Birth control pills
IUD
What to do if you can't find emergency contraception
How to Use It
Emergency contraception
Birth control pills as emergency contraception
IUD
How Well It Works
Emergency
contraception is not a replacement for regular
birth control
Learn more
Side Effects
References
Citations
Credits
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.