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Emergency Contraception: What You Need to Know

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on April 12, 2020.

What is an emergency contraceptive pill?

The emergency contraceptive pill is a safe and effective way to prevent pregnancy after unprotected sex, contraceptive failure or a sexual assault. Millions of women have safely used the emergency contraceptive pill and there have been no reports of serious complications or side effects. However, as with all drugs, there are directions for safe and effective use that must be followed.

  • The emergency contraceptive pill is frequently referred to as “The Morning After Pill” but this is a misnomer, as women do not have to wait until the morning after sex to take the emergency contraceptive pill.
  • Actually, the emergency contraceptive pill is more effective the sooner you take it -- as soon as possible after unprotected sex.

The emergency contraceptive pill has also been referred to as the ‘abortion pill’, but the emergency contraceptive pill cannot cause an abortion if a woman is already pregnant. It is only effective if used before a pregnancy is established. Emergency contraceptive pills have no action to terminate an already established pregnancy.

Emergency contraception will not protect you from HIV infection (the virus that causes AIDS) and other sexually transmitted diseases (STDs). Use a condom if there is any chance of contracting a sexually transmitted infection.

Do I need the Morning After Pill?

There are many valid reasons why emergency contraception may be needed. Some of these reasons include:

  • When a contraceptive method was desired but not used.
  • If there is a contraceptive failure, for example: a condom broke, a diaphragm, or cervical cap breakage, or a barrier contraceptive slippage.
  • If birth control pills, patches, rings or injections are started late or dislodged.
  • If there is failed withdrawal.
  • If there is expulsion of an IUD or implant.
  • Sexual assault; forced to have sex when you did not want to.

How does the emergency contraceptive pill work?

Levonorgestrel, the medication found in Plan B One Step, Take Action, Next Choice One Dose, My Way and other levonorgestrel emergency contraceptive pills prevent pregnancy by stopping or delaying the release of the egg from the ovary. Emergency contraceptive pills may also alter the lining of the uterus to prevent egg implantation or reduce the ability of the sperm to bind to an egg.

The levonorgestrel 1.5 mg emergency contraceptive pill should be taken within 72 hours after unprotected sex. It can lower your chance of getting pregnant by 75% to 89%, but it works best the sooner you take it.

Does weight affect the Morning After Pill?

Some research suggests that levonorgestrel emergency contraceptive pills may not be fully effective in women who are overweight or obese, but this is controversial topic.

  • The U.S. Food and Drug Administration (FDA) determined that a change in the labeling for emergency contraceptive products is not warranted in women who weigh more than 165 lbs (75 kg) or have a body mass index (BMI) of more than 25 kg/m2. However, the FDA also stated the data are conflicting and too limited to reach a definitive conclusion, but continues to believe all women, regardless of how much they weigh, can use these products to prevent unintended pregnancy following unprotected sexual intercourse or contraceptive failure.
  • However, studies have found that overweight or obese women using emergency contraceptive pills may have a greater risk of pregnancy than non-obese women.
  • The most effective choice for emergency contraception for overweight or obese women is the copper IUD with a 99% effectiveness rate. Also, the copper IUD can last for up to 10 years.
  • Talk to your healthcare provider how weight might affect your use of emergency contraceptive pills.

How does ella work?

Ulipristal, the progestin found in the emergency contraceptive pill ella, works to prevent pregnancy by blocking the natural hormone progesterone from occupying its receptor site in the body.

  • It is more effective than the levonorgestrel emergency contraceptive pill, and can be used up to 5 days (120 hours) after unprotected sex; however, it requires a prescription.
  • ella or the copper IUD may be a better option for emergency contraception in women if it has been more than 72 hours since unprotected sex. Call a doctor or clinic quickly.
  • After use of ella, a reliable barrier method of contraception (like a condom) should be used with sexual intercourse that occurs in that same menstrual cycle.
  • Wait at least 5 days after taking ella to resume oral contraceptives because they can lower the effectiveness of each other.

Can birth control pills be used for emergency contraception?

If you take combined birth control pills (often just called "the "pill") that contain both estrogen and progestin, and have no other options, higher doses can be used as an emergency contraceptive. They work by delaying ovulation, and the number of pills you would use for each brand of pill will differ between brands or generics. A doctor, clinic nurse, or pharmacist can tell you how many pills you should take based on the type and brand of oral birth control that you use.

If you should miss your period by more than one week, you should have a pregnancy test.

Side effects with the emergency contraceptive pill

Emergency contraceptive pills are very safe to use. Side effects, if they occur at all, are usually short-term and mild.

  • Nausea has been reported in about 20%, or 20 out of 100 women using levonorgestrel emergency contraception. Vomiting may also occur in about 4% of women.
  • If vomiting should occur within 3 hours of taking ulipristal (ella) or 2 hours of taking levonorgestrel emergency contraception (Plan B One Step and others), contact your healthcare provider as a repeat dose may be needed. You may also need an anti-nausea medication.

Other side effects may include:

  • irregular bleeding, spotting, or heavier bleeding
  • headache
  • dizziness
  • breast tenderness
  • fatigue
  • stomach pain.

Women who normally cannot use combined birth control pills because of medical conditions such as migraines, heart or liver conditions, or breastfeeding can usually still use the emergency contraceptive pill as it is just a one-time dose; speak to your doctor about your special situation in advance.

Does the emergency contraceptive pill end a pregnancy?

The EC pill will not stop an already established pregnancy. Studies have shown that emergency contraception pill use does not increase the risk to the developing fetus in women who may already unknowingly be pregnant. However, the emergency contraceptive pill should not be taken by a woman who knows that she is pregnant.

Emergency contraceptive pill products

In the U.S., the levonorgestrel emergency contraceptive pill can be obtained over-the-counter (OTC) without a prescription, an ID or age restriction. Levonorgestrel is the generic name of the progestin that is found in emergency contraceptives such as Plan B One Step and Next Choice One Dose.

  • Plan B and Next Choice, the original two-tablet regimens, are no longer marketed in the U.S. and have been replaced with Plan B One-Step and Next Choice One Dose, the one tablet levonorgestrel 1.5 mg regimen.

Another emergency contraceptive pill, ella, which contains a different progestin (ulipristal) is also available, but women must contact their physician as a prescription is required for ella.

Can I take ella and my birth control pill on the same day?

No, after using ella if a woman wishes to use hormonal contraception (like the pill), she should do so no sooner than 5 days after using ella. After use of ella, a barrier method of contraception (such as a condom) should be used for sex that occurs in that same menstrual cycle.

ella and the progestin component of hormonal contraceptives both bind to the progesterone receptor, and using them together could reduce the effectiveness.

Also, do not take ella with any other emergency contraceptive pill as it may also lower its effectiveness.

Can you use the IUD for emergency contraception?

Another option for emergency contraception is the insertion of the copper intrauterine device (IUD), also known as the ParaGard T 380A, up to 5 days after unprotected sex or a contraceptive failure.

  • The copper IUD is a T-shaped, hormone-free device that is inserted by a healthcare provider into the uterus to prevent pregnancy.
  • Pregnancy should be ruled out prior to insertion of a copper IUD. Overall, the copper IUD is the most effective form of emergency contraception -- up to 99% effective.
  • It is a hormone-free option.

The copper IUD works by making sperm less able to fertilize the women's egg or stops the egg from attaching to the wall of the uterus. An added plus, the copper IUD can be left in place for 10 years for long-term birth control. It can be removed by your healthcare provider if pregnancy is desired. If you need emergency contraception on the 4th or 5th day after unprotected sex, a copper IUD may be your most effective option.

The copper IUD form of contraception may be a good choice long-term for women who would prefer not to have to remember to take a pill every day. Women should discuss this option with their physician.

Mirena, an IUD that contains levonorgestrel, is not used as an emergency contraceptive.

List of Common Emergency Contraceptive Options

Generic name Common Proprietary Names Prescription required? Dose regimen
Levonorgestrel 1.5 mg, one tablet regimen
  • AfterPill
  • Athentia Next
  • Econtra EZ
  • Fallback Solo
  • Her Style
  • My Way Emergency Contracpetive
  • Next Choice One Dose
  • Opcicon One-Step
  • Plan B One Step
  • React Levonorgestrel
  • Take Action
  • No. Available to men and women regardless of age. No ID required.
  • Look for products in the family planning aisle.
  • Take one tablet as soon as possible after unprotected sex. The manufacturer recommends to take within 72 hours (3 days) after unprotected sex; the sooner the better.
  • On days 4 or 5 after unprotected sex, ella or the copper IUD may be a more reliable option for emergency contraception (see your doctor).
Levonorgestrel 0.75 mg, two tablet regimen
  • Next Choice and Plan B (and generics) no longer marketed in US.
  • May be available in other countries.

A two tablet regimen.

  • The first tablet should be taken as soon as possible within 72 hours after unprotected sex. The second tablet must be taken 12 hours later.
  • Alternatively, both tablets may be taken at the same time within 72 hours after unprotected sex.


Yes. Prescription required from health care provider.

  • Take tablet as soon as possible or up to 120 hours (5 days) after unprotected sex.
  • If you need emergency contraception on the 4th or 5th day after unprotected sex, ella may work better than levonorgestrel emergency contraceptive (Plan B One Step).
Copper IUD 

ParaGard T 380A

Yes. Insertion and removal required from a health care provider.

  • Inserted by a healthcare provider up to 5 days after unprotected sex or a contraceptive failure.
  • Hormone free; may be continued as long-term birth control for up to 10 years.

How do I take the emergency contraceptive pill?

Plan B One-Step and other levonorgestrel 1.5 mg tablets, 1-pill version

  • Plan B One Step, Next Choice One Dose, and others are available OTC as a single tablet of 1.5 mg of levonorgestrel. The manufacturer recommends the tablet in Plan B One-Step should be taken as soon as possible within 72 hours after unprotected sex.
  • Generic and proprietary brands of levonorgestrel 1.5 mg tablet are available.
  • Some studies have shown levonorgestrel 1.5 mg tablet can still be moderately effective up to 120 hours, or 5 days after unprotected sex. However, this may be dependent upon where you are in your ovulation cycle. As with all emergency contraceptive pills, they are more effective the sooner they are taken. Talk to your healthcare provider about this option. 


In addition to Plan B One Step, there is another type of emergency contraceptive pill called ella (ulipristal) that can also be used up to 5 days after unprotected sex.

  • ella contains 30 mg of ulipristal, and it works to prevent pregnancy by blocking the natural hormone progesterone from occupying its receptor site in the body.
  • ella lowers your chances of getting pregnant by 85% if you take it within 5 days after unprotected sex.

ella can be used up to 5 days after unprotected sex or a contraceptive failure but should be taken as soon as possible, as it is more effective the sooner it is taken. However, ella requires a prescription from your healthcare provider.

How often can I use the emergency contraceptive pill?

If unprotected sex should occur again, even within the same cycle, it is safe to use the levonorgestrel emergency contraceptive pill again if needed. However, a health care provider or clinic should be contacted as soon as possible so that a regular form of birth control can be started for ongoing contraceptive use.

Do not use ella (ulipristal) more than one time in the same menstrual cycle.

You should not use an emergency contraceptive pill as a regular method of birth control, because:

  • It can be costly and inconvenient.
  • It is not as effective as other options for birth control.
  • It may expose you to higher total levels of hormones.
  • It may lead to continued side effects, such as irregular periods, breast tenderness, or nausea.

If vomiting occurs within two hours of taking levonorgestrel emergency contraceptive or three hours of taking ella, you will need to repeat your dose. Contact your doctor.

Emergency contraceptive cost

Prices will vary, but in general the cash price (with discount coupon) of one regimen of over-the-counter levonorgestrel emergency contraceptive pill runs between $15 and $70 per package. Generics are typically less expensive, and you can ask your pharmacist if a lower cost option is available.

ella (ulipristal) also runs around $45 cash price, but remember it requires a prescription from your doctor. However, in many U.S. states, a pharmacist can give you a prescription for ella.

The copper IUD is expensive initially, but if continued as a long-term form of birth control, it can be very cost-effective. It is also convenient, as there is no need to remember to take a pill each day. The copper IUD can be left in place for up to ten years. Some insurance plans may pay for the IUD, as well. But if you are paying cash, the cost for an IUD, including insertion and office visit, typically runs between $500 and $1,300.

Learn More: Emergency Contraception Laid Bare: The 10 Biggest Myths Revealed

See Also


Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.