An Overview of Emergency Contraception

Emergency contraception (EC) is a birth control option that you can use to reduce your risk of getting pregnant after having unprotected sex or contraceptive failure. Depending on the method used, it either prevents ovulation or fertilization of an egg. So-called "morning-after pills" have been available for more than 30 years, and EC is a safe and effective method of birth control.

For the best effectiveness, emergency contraception needs to be used as soon as possible after unprotected sex or contraceptive failure.

Emergency contraception PlanB One-Step
Justin Sullivan / Getty Images

Why Some Use Emergency Contraception

Obviously, women who opt for emergency contraception do not wish to be pregnant at the time they take it. Common situations that lead to seeking out emergency contraception include:

  • Miscalculation of one's menstrual cycle and having sex on a day that they may have been fertile
  • Not using any birth control during sex
  • Not taking normal birth control method as directed
  • A condom broke or slipped off during sex
  • A male partner did not pull out in time
  • A diaphragm, cervical cap, or shield moved out of place during sex or spermicide was not used
  • The Today Sponge was taken out too soon
  • Forced unprotected sex

Generally speaking, most women who want to use emergency contraception can safely use it—this even applies to women who are not usually good candidates for using hormonal birth control as their main form of contraception.

Emergency contraception can also be safely used by teenagers.

If you believe that you could have experienced birth control failure in any way, and you do not wish to be pregnant, you may want to consider using emergency contraception.

Options and How They Work

Over the past few years, emergency contraception options have greatly expanded.

Many types of emergency contraception contain the same hormone (a progestin) that is found in some birth control pills. However, Ella blocks the activity of the progesterone in the body. Overall, these medications work by preventing or delaying ovulation, depending on where you are in your cycle. Essentially, it works to make sure sperm has no egg to fertilize.

Such options include:

  • Plan B One-Step is a progestin-only 1.5 milligram (mg) levonorgestrel pill. It is available over the counter, without prescription. Generic equivalents include Next Choice One Dose, Fallback Solo, My Way, Opcicon One-Step, Take Action, EContraEZ, and many others. AfterPill is a generic equivalent that can only be bought online.
  • Ella (ulipristal acetate) is a 30 mg pill available only by prescription. This drug has a longer window of action than the progestin pill and works to block the action of progestin in maturing and releasing an egg.

Oral contraceptives used for regular contraception can also be used as EC. Doing so involves taking a specific regimen of prescription oral contraceptive pills—either progestin-only birth control pills (norethindrone 0.35 mg pills) or combined oral contraceptives—in two doses, 12 hours apart.

The number of pills taken will depend on the brand and type, so it is best to consult your healthcare provider or pharmacist for advice on how many to take and when. This method also works by delaying ovulation.

Another option, the ParaGard IUD works to make sperm less able to fertilize an egg and to make the uterine lining less receptive to implantation by a fertilized egg. Unlike the above options, it does not prevent the release of an egg.

This copper-releasing IUD is used by many women to routinely prevent against pregnancy, but may be implanted by a healthcare provider as a means of emergency birth control as well. Thereafter, the device can then be left in place for ongoing contraception for up to 12 years.


In order to reduce your risk of pregnancy, emergency contraception should be started up to five days (120 hours) after unprotected sex. The sooner it is used, the better the chances of preventing pregnancy.

With the morning-after pills Ella (ulipristal acetate) and Plan B One-Step (and its generic versions), you only need to swallow one pill. The discontinued Next Choice was a two-pill regimen, but it has been replaced by Next Choice One Dose.

The manufacturers suggest that these pills should be used within 72 hours of contraceptive failure or unprotected sex—but again, the sooner the better. That being said, it may still be useful to take the morning-after pill to take to decrease your chances of pregnancy up to five days after unprotected sex or contraceptive failure.

When used as emergency contraception, the ParaGard IUD should be inserted within five days after unprotected sex or contraceptive failure. It may then work to prevent pregnancy for several years.


In general, emergency contraception is meant to be a backup birth control method. It is not as effective as the correct and consistent use of other reversible prescription birth control methods.

All methods of emergency contraception reduce the risk of pregnancy by 75% to 99% when they are initiated within 72 hours.  This means that out of every 100 women who use any EC method, between one and 25 will become pregnant.​

EC Type Effectiveness*
ParaGard IUD 99.9%
Ella (ulipristal acetate) 94%
Plan B One-Step and generics 87%
Combined regimen of estrogen and progestin birth control pills 75%
*When used as directed

Two main factors influence the effectiveness of emergency contraception:

  • The amount of time that has gone by since the incident of unprotected sex/birth control failure
  • The point in your cycle when you had sex: The closer you are to ovulation (after having unprotected sex or experiencing birth control failure), the less effective emergency contraception will be.

Side Effects

Side effects may vary depending on the type of emergency contraception you are using. You should discuss any major side effects with your healthcare provider. This is especially true if you end up vomiting after taking EC, as your practitioner can advise as to if you should take another dose.

If you are experiencing any signs of pregnancy after using emergency contraception, it is also important to contact your practitioner. Some of the most common pregnancy signs include:​

  • Delayed menstrual period
  • Heavier menstrual bleeding
  • Sore or enlarged breasts
  • Nausea
  • Unexplained fatigue
  • Headaches

Because it is still unknown if Ella causes any risks to a developing fetus, you should not take Ella if you suspect you are already pregnant. Take a pregnancy test at your healthcare provider's office before getting this prescription.

Special Considerations

The morning-after pill, rather than an IUD, may be a safer choice for women at increased risk for sexually transmitted diseases (STDs). This includes, but is not limited to, women who have had unprotected sex with infected partners, have experienced sexual assault, or who use IV drugs (or have a partner who does).

Bacteria from a preexisting infection can be introduced into the uterus during IUD insertion. If this is left untreated, it can lead to pelvic inflammatory disease.

Also of note, research suggests that the effectiveness of the EC pills might be less in women with obesity. While the evidence is only fair to poor quality, this could be a concern. In these cases, use of the emergency copper IUD might be preferred. Women may also want to have EC pills on-hand so they may be taken without delay for the best effectiveness.

What Emergency Contraception Is Not

Emergency contraception of any kind is not a means of STD protection or ongoing pregnancy prevention. Other birth control methods should be used after you use EC if you do not wish to be pregnant.

Some people confuse emergency contraceptive pills with the abortion pill (RU486). These two medications serve very different purposes and do not work in the same way.

Emergency contraceptive pills cannot end a pregnancy and should not hurt an existing pregnancy.

Scientific and medical authorities are in agreement that emergency contraception reduces the risk of pregnancy (with the same action as regular birth control pills). This helps women avoid having to face the choice of whether or not to have an abortion, if one would be considered, in the case of unintended pregnancy.

Still, there is some public opposition to emergency contraceptive on various grounds, including opposition to any artificial birth control means, confusion as to whether it might terminate a pregnancy, and parental concerns over their child's use of contraception without their knowledge or consent.

How and Where to Get It

Plan B One-Step (and its generic alternatives) can now be purchased over-the-counter by people of any age—thanks to the court case Tummino v. Hamburg.

Other forms of emergency contraception can only be obtained with a prescription (like Ella); ParaGard must be inserted by a medical professional. As such, these EC options require a healthcare provider's appointment.

Because timing is a concern with emergency contraception, call your pharmacy/drugstore before you go there to make sure that they have what you need in stock.

Some stores may keep these forms of EC at the pharmacy counter, and the pharmacy may be closed even if the store is still open. It may be a good idea to buy a pack of one of the morning-after pills to already have at home—this way, if you need it, you can take it immediately.

History of Availability

Emergency contraceptive products were first available by prescription only in 1998. In 2006, those age 18 and over could buy them over the counter. The FDA approved over-the-counter purchase of these drugs by women of all ages without prescription in June 2013.

Until 2016, there was a wrinkle in how generic products were labeled, as Plan B One-Step was the only product allowed to be labeled as being available for people of all ages; generic labels were required to say the drugs were intended for use in women 17 years of age or older (although they could be sold to anyone). This label requirement had to do with politics rather than safety.

This mandate expired in 2016, so confusion should now be eliminated.


The cost for emergency contraception widely varies and depends upon the EC method. Total fees can range from about $40 to $50 for Plan B One-Step; its generic alternatives are typically priced around 10% to 20% less. Ella usually costs $50 or more, and it can cost up to around $1000 to obtain the ParaGard IUD.

Even though Plan B One-Step, Take Action, Next Choice One Dose, My Way, Fallback Solo, Opcicon One-Step, and EContraEZ are all available over-the-counter, you may still need a prescription (regardless of your age) in order for your insurance to cover the cost of these medications, so be sure to check your health policy's rules.

Privacy Concerns

Being able to buy EC pills over the counter allows women of any age to procure them discreetly. However, note that obtaining a prescription option may open you up to privacy concerns. For example, if you are a teen on your parent's health insurance, it is likely they will receive paperwork regarding services and payments.

A Word From Verywell

Almost half (45%) of the 6.1 million pregnancies in the United States each year are unintended. Many of these pregnancies are due to contraceptive failure or not using birth control. Emergency contraception offers you a last-chance option to prevent pregnancy. It is safe and effective.

14 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. World Health Organization. Emergency contraception.

  2. American College of Obstetricians and Gynecologists. Emergency contraception.

  3. Gemzell-Danielsson K, Berger C. Emergency contraception—mechanisms of action. Contraception. 2013 Mar;87(3):300-8. doi: 10.1016/j.contraception.2012.08.021

  4. Planned Parenthood. Should I get a copper or a hormonal IUD?

  5. Centers for Disease Control and Prevention. Emergency contraception.

  6. U.S. Food & Drug Administration. Plan B One-Step (levonorgestrel) [labeling].

  7. U.S. Department of Health and Human Services. Emergency contraception.

  8. Jatlaoui TC, Curtis KM. Safety and effectiveness data for emergency contraceptive pills among women with obesity: a systematic review. Contraception. 2016;94(6):605–611. doi:10.1016/j.contraception.2016.05.002

  9. Najera DB. Emergency contraception: Focus on the facts. JAAPA. 2016;29(1):20-4. doi:10.1097/01.JAA.0000475459.00348.81

  10. Tummino v. Hamburg, 936 F. Supp. 2d 162 - Dist. Court, ED New York

  11. Food and Drug Administration. Reference ID: 3460250.

  12. Planned Parenthood. What's the Plan B Morning-After pill?

  13. University of Michigan: University Health Services. Contraception Cost, Insurance and Payment.

  14. Planned Parenthood. What's the ella morning-after pill?

Additional Reading
Dawn Stacey

By Dawn Stacey, PhD, LMHC
Dawn Stacey, PhD, LMHC, is a published author, college professor, and mental health consultant with over 15 years of counseling experience.