Emergency Contraception

  • Medical Author: Omnia M Samra, MD
  • Medical Editor: Bryan D Cowan, MD
  • Medical Editor: Francisco Talavera, PharmD, PhD
  • Medical Editor: Lee P Shulman, MD

What is Emergency Contraception?

Emergency contraception is a drug or device used to prevent pregnancy after unprotected sex.
Emergency contraception is a drug or device used to prevent pregnancy after unprotected sex.
  • Emergency contraception (birth control after sexual intercourse) is the use of a drug or device to prevent pregnancy after unprotected sexual intercourse.
  • Emergency contraception can be used when a condom breaks, if a diaphragm or cervical cap slips out of place during intercourse, after a sexual assault, or any time unprotected intercourse occurs.
  • Emergency contraceptive pills are sometimes called the “morning-after pill,” but they are usually effective if taken within 72 hours of unprotected sexual intercourse.
  • Emergency contraceptives available in the United States include emergency contraceptive pills, which contain the same hormones found in birth control pills, and the Copper T380 intrauterine device (IUD).
  • The Preven kit, the Plan B kit and Ella are pills marketed as emergency contraceptive pills.
  • Emergency contraceptive measures can be taken within the first 72 hours after unprotected sexual intercourse to reduce the possibility of pregnancy.
  • A woman is most likely to become pregnant if sexual intercourse occurs in the few days before or after ovulation (release of an egg from the ovary).
  • Emergency contraceptives should not be used as a contraceptive method in women who are sexually active or planning to become sexually active. They are not as effective as any ongoing contraceptive method.

What Should I Know About Emergency Contraceptive Pills (Morning After Pill)?

  • Some emergency contraception pills contain high doses of the same hormones that are in birth control pills. The high dose of hormones is short lived. Cases of deep vein thrombosis (blood clotting) have been reported in women using this emergency birth control method.
  • These pills are not designed to terminate an existing pregnancy and should not be confused with Mifeprex, also referred to as RU-486, which is used to terminate (abort) an existing pregnancy. Emergency contraceptive pills are taken in 2 doses, 12 hours apart. The Preven plan consists of 2 doses of pills, each containing a combination of estrogen and progestin, taken 12 hours apart.
  • The first dose should be taken within the first 72 hours after unprotected intercourse. Some studies show they are effective if taken after that time (up to 120 hours), but they are most effective in the first 72 hours. According to the Reproductive Health Technologies Project, Preven reduces the chance of pregnancy by 75% when used as directed.
  • Plan B is a progestin-only emergency contraceptive. Plan B should be used within 72 hours of unprotected intercourse. The first dose should be taken as soon as possible after unprotected intercourse, and the second dose is taken 12 hours later. The sooner it is used, the more effective it is. According to the Reproductive Health Technologies Project, Plan B reduces the chance of pregnancy by 89% when used as directed.
  • Some other kinds of birth control pills can also be used for emergency contraception. The dosage depends on the brand. Consult your health care provider to learn about options. The sooner after intercourse that emergency contraceptive pills are taken, the more effective they are.
  • Ella is a unique type of emergency contraception that is a single pill taken up to 5 days after intercourse. It is a progesterone antagonist/agonist that affects the implantation of a pregnancy.
  • Emergency contraception pills are currently available without a prescription. Prices for emergency contraceptive pills generally range from $8 to $50. It can be purchased at most pharmacies.

What Is the Emergency Intrauterine Device (IUD)?

The IUD used for emergency contraception is the Copper T 380A IUD (ParaGard). It can be inserted up to 5 days after unprotected sexual intercourse but should be inserted as soon as possible. The IUD can be removed after your next menstrual period, when it is confirmed that you are not pregnant.

You can use the IUD for long-term birth control. The copper IUD can be left in place for up to 10 years for contraception, and it is a reversible form of birth control. Planned Parenthood cites emergency IUD insertion as being 99.9% effective.

After IUD insertion, you may wish to have someone drive you home and to rest afterwards. IUDs should only be inserted and removed by health care professionals. The costs associated with a ParaGard IUD generally are about $750 for exam, IUD, and insertion. This type of IUD can be left in place for up to 10 years.

Are Emergency Contraceptive Pills (Morning After Pill) Effective?

Emergency contraception prevents pregnancy by stopping or delaying release of an egg (ovulation), blocking fertilization by affecting the egg or sperm, or preventing implantation by making the lining of the uterus inhospitable for pregnancy.

Pregnancy is defined by the medical community as implantation of a fertilized egg in the lining of a woman’s uterus, so emergency contraception works before pregnancy has occurred.

A pregnancy test is not useful because emergency contraception is used to prevent pregnancy rather than to abort an existing pregnancy. A woman who uses emergency contraception will never know if a pregnancy would have otherwise occurred. Fertility returns with the next cycle unless a birth control method is continued.

In order for emergency contraceptive pills to be effective, they must be taken as directed. Carefully follow the package instructions that come with the emergency contraceptive you choose.

Do I Need to See a Doctor for Emergency Contraception?

While you can obtain some emergency contraceptive pills like Plan B (not all emergency contraception options) without seeing a doctor, a visit with a healthcare provider may be helpful in your situation. It is important to ask yourself these questions before considering the use of emergency contraception.

  • Is it possible that you are already pregnant?
  • Do you use any sort of contraception regularly?
  • Is it possible that you have been exposed to sexually transmitted infections?

How Effective Is Emergency Contraception?


  • According to Planned Parenthood and the Reproductive Health Technologies Project, if taken within the first 72 hours of unprotected intercourse, emergency contraceptive pills are 75-89% effective in reducing the risk of pregnancy.
  • The effectiveness rate of 75% does not mean a 25% failure rate. Instead, when considering 100 women who have had unprotected intercourse during the middle 2 weeks of their cycle, about 8 became pregnant. If those 8 had used emergency contraception, only 2 would have become pregnant.
  • Emergency contraception pills work best when used as soon as possible after unprotected sexual intercourse. Planned Parenthood cites emergency IUD insertion as being 99.9% effective. Ella is more effective than other oral medications, but less effective than the IUD.


  • Emergency contraception is a safe form of backup birth control if your birth control fails or if you have unprotected sexual intercourse. It is used after intercourse but before pregnancy has occurred. After use, fertility returns to normal unless a form of birth control is continued.


  • Common side effects of emergency contraceptive pills are similar to those of birth control pills.
  • They include nausea, abdominal pain, fatigue, headache, and menstrual changes.
  • Breast tenderness, fluid retention, and dizziness may also occur.
  • Many of these symptoms may be less severe with progestin-only or intrauterine forms of emergency contraception.
  • Serious risks include heart attack, blood clots, and strokes.
  • Emergency contraceptive pills do not continue to protect against pregnancy during the rest of the cycle.
  • Emergency contraception may not prevent tubal pregnancy. If you experience severe abdominal pain, contact your health care provider immediately. Tubal pregnancy can be life threatening.
  • Side effects of IUDs used for emergency contraception are the same as those for ongoing birth control IUDs. Emergency contraception does not protect against sexually transmitted infections, nor does it treat existing infections.

Women who should not use emergency contraception

  • Women who are pregnant, those with undiagnosed vaginal bleeding, and women with an allergy to the product should not use emergency contraceptive pills.
  • IUD use for emergency contraception is not recommended for women who are not in an established monogamous relationship and those who have been raped. See Birth Control Intrauterine Devices for more information about IUDs.

Should I Call the Doctor after Emergency Contraception?

If you experience severe abdominal pain, this could be a sign of tubal pregnancy, a condition that requires emergency medical care. Contact your health care provider immediately.

Emergency contraception pills are not 100% effective in preventing pregnancy, even when taken within 72 hours of intercourse. You still have a risk for pregnancy. You may need follow-up care if your normal menstrual cycle does not occur. Contact your health care provider if you do not have your period within 3 weeks of using emergency contraception or have symptoms of pregnancy.

Contraceptive pills do not provide any protection against sexually transmitted diseases. Consider testing for sexually transmitted infections if the unprotected intercourse may have put you at risk. You may need follow-up care in the next few weeks if you develop any symptoms of sexually transmitted infections, such as pain, itching, sores, or discharge.

What Other Types of Birth Control Can Prevent Pregnancy?

Emergency contraception is not as effective as ongoing birth control. It should not be used routinely instead of birth control. If you are sexually active and wish to avoid pregnancy, you may wish to consider using a consistent form of birth control.

Many methods of birth control are available, both by prescription and over the counter. If you have questions about which is best for you, ask your health care provider or contact your local Planned Parenthood (800-230-PLAN).

Birth Control Methods

  • If you are of childbearing age, you may consider using a form of birth control to prevent becoming pregnant.
  • The practice of preventing pregnancy is as old as human existence. For centuries, humans have attempted to avoid pregnancy at certain times of their lives to accommodate their careers, marital situations, and preferences.
  • The ability to control whether and when you become pregnant can affect your ability to achieve your own goals and can contribute to your sense of well-being.