Emergency Contraception: What You Need to Know

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on May 6, 2024.

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 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.

Also, it's a good idea to get emergency contraception before you need it, instead of waiting to the last minute. That way you can take it as soon as possible and don't have to hunt for an open pharmacy or get a prescription.

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.

As reported by the manufacturer, Plan B One‑Step is not an abortifacient, will not affect a pregnancy that has already begun, and it will not impact a woman’s future fertility.

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.

Which emergency contraceptive pills are available in the U.S?

In the U.S., the levonorgestrel emergency contraceptive pill can be obtained over-the-counter (OTC) without a prescription, without identification 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. They can be found at pharmacies, some groceries and other retail shops.

Another emergency contraceptive pill, ella, which contains ulipristal is also available, but women must contact their healthcare provider as a prescription is required for ella.

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. Generic and more affordable options may be available - ask your pharmacist.

Table 1. Common Emergency Contraceptives

Generic name	Common names	Prescription required?	How to take
Levonorgestrel 1.5 mg, one tablet regimen	AfterPill Athentia Next Fallback Solo Her Style My Way Opcicon One-Step Plan B One Step React	No. Available regardless of age or sex. No ID required. Look for products in the family planning aisle of pharmacies or other retail shops.	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 (contact your doctor).
Levonorgestrel 0.75 mg, two tablet regimen	Next Choice and Plan B (and generics) are no longer marketed in U.S. May be available in other countries.	Not available in U.S. 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.
Ulipristal	ella	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, the ella pill may work better than levonorgestrel emergency contraceptive pill (Plan B One Step).
Copper IUD	ParaGard	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. Can be used effectively by women of any weight.
Hormonal IUD (containing 52 mg levonorgestrel)	Only use hormonal IUDs that contain 52 mg levonorgestrel (for example: Liletta or Mirena) (Note: Recommended by medical resources but listed as a contraindication by manufacturers). Do not use Skyla or Kyleena for emergency contraception.	Yes. Insertion and removal required from a health care provider.	Inserted by a healthcare provider within 5 days after unprotected sex or a contraceptive failure. May be continued as long-term birth control for up to 8 years (Liletta or Mirena).

Do I need the emergency contraceptive?

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

• You had unprotected vaginal sex in the last 5 days (120 hours).
• You used your regular form of birth control wrong, for example:
  • If you have a contraceptive failure: a condom, diaphragm, cervical cap, patch or barrier contraceptive broke, fell off, tore, or slipped.
  • If birth control pills, patches, rings or shots are started late or dislodged.
  • If a spermicidal contraceptive tablet fails to melt before sex.
  • If there is failed withdrawal ("pull out") during vaginal sex.
  • If your intrauterine device (IUD) or implant falls out.
  • If you take an oral birth control pill (by mouth) and missed taking it by more than the recommended time.
  • You were a victim of sexual assault and forced to have sex when you did not want to.

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 over-the-counter (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. Ask your pharmacist. Generic products may be less pricey.
• 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. Talk to your healthcare provider or pharmacist about this option.
• As with all emergency contraceptive pills, they are more effective the sooner they are taken. 

ella

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. After using ella, do not use any additional levonorgestrel emergency contraceptive pills (like Plan B One Step) within 5 days after taking ella.

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.

How does the emergency contraceptive pill work?

Levonorgestrel, the medication found in Plan B One Step, 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 (called ovulation). 

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.

How does weight affect emergency contraception?

IUDS

The most effective choice for emergency contraception for overweight or obese women weighing 165 pounds [75 kg] or more is the copper IUD or the hormonal IUD (for example: Liletta, Mirena) IUD. These products have a 99% effectiveness rate when inserted within 5 days of unprotected sex.

IUDs can then remain in place for up to 7 to 10 years as effective, long-term birth control (based on the recommendations for each product). 

Overall, the copper IUD is the most effective form of emergency contraception, regardless of weight.

Levonorgestrel 1.5 mg (Plan B One Step)

Some research suggests that levonorgestrel emergency contraceptive pills may not be fully effective in women who are overweight or obese. Studies have found that overweight or obese women using emergency contraceptive pills may have a greater risk of pregnancy than women who are not overweight or obese.

However, the manufacturer of Plan B One Step and the FDA still state that all women, regardless of how much they weigh, can use Plan B One Step (levonorgestreol 1.5 mg) to prevent unintended pregnancy following unprotected sex or a contraceptive failure. The most important factor affecting how well Plan B works is how quickly it is taken.

Talk to your healthcare provider how weight might affect your use of emergency contraceptive pills.

How does ella work?

ella works to prevent pregnancy by blocking the natural hormone progesterone from occupying its receptor site in the body. ella is thought to work for emergency contraception mainly by stopping or delaying the release of an egg from the ovary and possibly by preventing attachment (implantation) to the uterus.

The risk of pregnancy is 1% to 2% after taking ella within 5 days (120 hours) after unprotected sex, but works best if you take it as soon as possible. This means that 1 to 2 people out of every 100 people who use this type of emergency contraceptive will get pregnant anyway.

ella 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 from a healthcare provider. Call a doctor or women's health clinic for an ella prescription or appointment quickly due to the 5 day limit.

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.

Ella is meant for emergency contraception only and is not to be used frequently or as a regular birth control. Contact a healthcare provider to discuss a form of ongoing birth control.

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

No, after using ella if you want to use hormonal contraception (like the pill, patch or vaginal ring), you should do so no sooner than 5 days after using ella. After using Ella, you should also use a reliable barrier birth control method (such as condom with spermicide) each time you have sex until your next menstrual period.

ella and the progestin component of hormonal contraceptives both bind to the progesterone receptor, and using them together could reduce the effectiveness of each. Also, do not use any additional levonorgestrel emergency contraceptive pills within 5 days after taking ella.

Wait at least 5 days after taking ella to resume regular hormonal contraceptive use (such as the pill, patch or vaginal ring) because they can lower the effectiveness of each other. Use a reliable barrier method (like a condom) until the next menstrual period.

Do not use any additional levonorgestrel emergency contraceptive pills within 5 days after taking Ella.

To learn more about ella, see: ella uses, dosage and side effects

Can regular birth control pills be used for emergency contraception?

If you take combination oral birth control pills that contain both estrogen and progestin, and have no other options, higher doses can be used as an emergency contraceptive. A doctor, clinic nurse, or pharmacist can tell you how many pills you should take based on the type of oral birth control that you use. Contact them immediately.

Combination oral contraceptives work by delaying ovulation, and the number of pills you would use for each brand of pill will differ between brands or generics. They don't work as well as other forms of emergency contraception but is better than no option at all. They may also increase your risk of nausea. Contact your healthcare provider if you vomit within 3 hours of taking the medicine as you may need a repeat dose.

If you should miss your period by more than one week, take a pregnancy test or get one from your healthcare provider.

What are the side effects of the emergency contraceptive pill?

Emergency contraceptive pills are very safe to use. Side effects with levonorgestrel, the most commonly used emergency contraceptive pill, are usually short-term and mild, if they occur at all.

Nausea has been reported in about 20% (20 out of 100) of 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 doctor or pharmacist as a repeat dose may be needed. You may also need an anti-nausea medication.

Other side effects 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. Ask your healthcare provider for advice.

Does the emergency contraceptive pill end a pregnancy?

The emergency contraceptive 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.

Learn more: Emergency Contraceptives Available in the U.S.

Can you use the IUD for emergency contraception?

Yes, some IUDs (Paragard, Liletta, Mirena) can be used as emergency contraceptives, but they must be inserted by a health care provider within 5 days of unprotected sex, but can be used as a long-term form of birth control after inserted.

An IUD may be more costly up front, but your insurance or family planning clinic may be able to cover some or all of the costs for an IUD. Call your doctor or local women's health clinic as soon as possible for an appointment. Tell them why you need an appointment, since time is important.

An IUD is protective against pregnancy by more than 99% if you get it put in within 5 days of unprotected sex. The IUD form of birth control may also be a good long-term choice for women who would prefer not to take a pill every day. IUDs may also work better in women who weigh more than 165 lbs (75 kg).

How effective is the copper IUD as an emergency contraceptive?

One 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. It is a hormone-free option. Overall, the copper IUD is the most effective form of emergency contraception -- over 99% effective.

The copper IUD is a T-shaped, hormone-free device that is inserted by a healthcare provider into the uterus to prevent pregnancy.

• 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.
• The copper IUD can be left in place for 10 years for long-term birth control. It can be removed by your healthcare provider later 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.

Can the hormonal IUD be used as emergency contraceptive?

In addition to the copper IUD (Paragard), two brand names of hormonal IUDs can also be used for emergency contraception -- Liletta or Mirena, according to resources like Planned Parenthood. It should be inserted within 5 days after unprotected sex or a contraceptive failure. These products both contain 52 mg of levonorgestrel.

IUDs that contain less than 52 mg of levonorgestrel, such as Kyleena and Skyla, should not be used as emergency contraceptives, as noted in the product labeling.

How much do emergency contraceptives cost?

Prices will vary, but in general the cash price (with an online discount coupon) of one regimen of over-the-counter levonorgestrel emergency contraceptive pill runs between $12 and $50 per package. Generics are typically less expensive, and you can ask your pharmacist which low cost option is available.

ella (ulipristal) also runs around $50 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.

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.

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 10 years.

This is not all the information you need to know about emergency contraceptives for safe and effective use and does not take the place of your healthcare provider's directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.

See also

• Birth Control Pills - When Should I Expect My Period?
• Birth Control Pills: Benefits, Risks & Side Effects
• Birth Control Pills: Why do I get breakthrough bleeding?
• Emergency Contraceptives: Morning After Pills & OTC Options
• Grapefruit and Birth Control Pills: Your Questions Answered
• Missed your birth control pill? Here's what to do
• Non-hormonal Methods of Birth Control
• What are the options for permanent birth control?
• Your Guide to Types of Birth Control Pills (Oral Contraceptives)

Further information

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