Emergency contraception

Consult an OB-GYN about alternate contraceptive options if you have taken the morning-after pill several times, said Dr. Maslow.

How Many Times Can You Take Plan B?

You can take the morning-after pill as many times as you need. Still, other birth control options may be more reliable.

Updated on August 31, 2023
Medically reviewed by

Renita White, MD, is an obstetrician/gynecologist at Georgia Obstetrics and Gynecology in Atlanta, Georgia. Her areas of expertise include fibroids, irregular vaginal bleeding, abnormal pap smears, infertility and menopause.

You can take Plan B, or the “morning-after pill,” as often as needed to prevent an unplanned pregnancy after unprotected sex. Plan B and other forms of emergency contraception do not have long-term effects if you use them multiple times.

Still, the Office on Women’s Health (OWH) advises not using the morning-after pill as a regular form of birth control. You might consider other options like condoms, hormonal options—like pills, patches, shots, and vaginal rings—and IUDs if you often use the morning-after pill.

Read on to learn about morning-after pills, how to use them, and short- and long-term side effects.

IAN HOOTON/SPL/Getty Images

What Is a Morning-After Pill?

One of the most common morning-after pills is Plan B (levonorgestrel), a synthetic form of the hormone progesterone. You can buy Plan B over the counter as tablets. Another over-the-counter option is ella (ulipristal). Those pills delay or prevent the ovary from releasing an egg. As a result, the risk of sperm fertilizing an egg lowers.

A copper or hormonal intrauterine device (IUD) inserted within five days of unprotected sex is another emergency contraception option.

Of note: The morning-after pill is not 100% effective at preventing pregnancy but can prevent more than 95% of pregnancies.

The Food and Drug Administration has not approved the morning-after pill as routine birth control. Taking regular birth control pills at the same time daily is much more effective than the morning-after pill at preventing pregnancy.

When To Take a Morning-After Pill

The morning-after pill works best if you take it as soon as possible. Plan B works up to 72 hours after unprotected sex, while ella is effective for 120 hours.

Side-Effects of Morning-After Pills

You might have unpleasant side effects after taking the morning-after pill, Christine Greves, MD, an OB-GYN at Winnie Palmer Hospital for Women and Babies, told Health.

Morning-after pill side effects include:

• Abdominal pain
• Breast pain
• Fatigue
• Feeling dizzy
• Headache
• Nausea

Long-Term Effects

Ella and Plan B generally do not have harmful long-term effects on your body. The morning-after pill does not have any long-term impact on future fertility.

Still, taking the morning-after pill multiple times can affect your hormones, Sherry Ross, MD, an OB-GYN based in Los Angeles and author of “She-ology,” told Health. For example, you may notice that your next period arrives earlier or later than usual after taking the morning-after pill. Spotting between periods is not unusual.

“[The morning-after pill is] temporarily harmful in that you will have irregular bleeding and may feel emotionally unraveled,” said Dr. Ross. “Once you stop taking it, your body will have the opportunity to reset.”

When Should You Take Plan B?

Taking a morning-after pill after every unprotected sexual encounter is essential for preventing pregnancy. Say you have unprotected sex a few days after taking a morning-after pill. In that case, taking another morning-after pill is the safest option.

“In theory, [the morning-after pill] should cover you until your next period because of the changes it causes in the uterine lining,” Bat-Sheva Lerner Maslow, MD, a reproductive endocrinologist based in New Jersey, told Health. “I wouldn’t necessarily recommend relying on it as a proactive form of birth control.”

Consult an OB-GYN about alternate contraceptive options if you have taken the morning-after pill several times, said Dr. Maslow.

A reliable form of contraception may be more helpful than constantly turning to emergency ones, added Dr. Maslow. For example, long-term contraception such as an IUD can make forgetfulness a non-issue if you often forget to take birth control pills.

Frequently Asked Questions

Should I take plan B just in case if I’m on birth control?

You do not need to use Plan B or another form of emergency contraception if you use birth control. Taking birth control pills at the same time daily helps protects you from pregnancy. You do not need to use Plan B if you have unprotected sex during your placebo pill week. Birth control pills still work during that time. Do not take other birth control pills that contain progesterone for at least five days after using ella, said Dr. Greves. Other forms of progesterone may interfere with the ella’s effectiveness.

How do you know if you should use Plan B?

• A condom breaks
• A diaphragm becomes misplaced
• You do not use birth control correctly (e.g., you forget to take your birth control at the same time every day)
• You do not use other types of birth control

Emergency contraception is an option after sexual assault or rape.

What makes Plan B less effective?

• Certain medications: Rifampin, an antibiotic, and griseofulvin, an antifungal, may affect how well the morning-after pill works. Consult a healthcare provider if you take anti-seizure and HIV medicines or use the herb St. John’s wort.
• Timing: The morning-after pill becomes less effective the longer you wait. Consider ella if it has been more than three days since having unprotected sex. The morning-after pill will not work after you start ovulating.
• Weight: Some evidence suggests that the morning-after pill may be less effective in people with a higher body mass index (BMI) than others. Consult a healthcare provider if you are overweight or have obesity and need an emergency contraceptive. A copper or hormonal IUD placed within five days of unprotected sex helps prevent pregnancy, regardless of weight.

A Quick Review

You may notice fatigue, nausea, and spotting between menstrual periods after taking a morning-after pill. Taking Plan B or another type of morning-after pill multiple times likely will not cause any long-term harm.

Still, you might consider long-term forms of birth control if you often take the morning-after pill. Other types of birth control include condoms, hormonal options—like pills, patches, shots, and vaginal rings—and IUDs. Consult a healthcare provider about the best option for you.

Was this page helpful?
Thanks for your feedback!
Tell us why!
12 Sources

Health.com 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. Office on Women’s Health. Emergency contraception.
2. Office on Women’s Health. Birth control methods.
3. MedlinePlus. Levonorgestrel.
4. MedlinePlus. Ulipristal.
5. Centers for Disease Control and Prevention. Contraception.
6. World Health Organization. Emergency contraception.
7. Planned Parenthood. The morning after pill: Just the facts.
8. Planned Parenthood. Can you get pregnant if you have unprotected sex one day after taking the morning-after pill?.
9. Planned Parenthood. Do I need to take Plan B after my period if I’m on birth control pills?.
10. MedlinePlus. Emergency contraception.
11. Planned Parenthood. The morning-after pill doesn’t work for every body — three things you need to know.
12. 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

Related Articles

Does Plan B Expire?
What Is a Birth Control Sponge?
What You Need To Know about Diaphragm Birth Control
How Long Is Too Long to Be on Birth Control?
What to Expect When Stopping Birth Control
What Is the Best Birth Control?
What Does Getting an IUD Feel Like?
Everything You Need To Know About an IUD
How Does IUD Insertion Work?
Does IUD Removal Hurt? What You Should Know
Does Birth Control Make You Gain Weight?
Does Nexplanon Cause Acne?
9 Effects of Going Off Birth Control
The Best Birth Control Options To Consider for Your 20s and Beyond
What Is Birth Control?

• About Us
• Medical Expert Board
• Editorial Process
• Diversity Pledge
• Privacy Policy
• Product Vetting
• Terms of Service
• Careers
• Advertise
• Contact
• EU Privacy

Health’s content is for informational and educational purposes only. Our website is not intended to be a substitute for professional medical advice, diagnosis, or treatment.

Health is part of the Dotdash Meredith publishing family.
Newsletter Sign Up
Newsletter Sign Up

We Care About Your Privacy

We and our 100 partners store and/or access information on a device, such as unique IDs in cookies to process personal data. You may accept or manage your choices by clicking below, including your right to object where legitimate interest is used, or at any time in the privacy policy page. These choices will be signaled to our partners and will not affect browsing data.

We and our partners process data to provide:

Store and/or access information on a device. Use limited data to select advertising. Create profiles for personalised advertising. Use profiles to select personalised advertising. Create profiles to personalise content. Use profiles to select personalised content. Measure advertising performance. Measure content performance. Understand audiences through statistics or combinations of data from different sources. Develop and improve services. Use limited data to select content. List of Partners (vendors)

Emergency contraception

The intrauterine device shown uses copper as the active contraceptive, others use progesterone in a plastic device. IUDs are very effective at preventing pregnancy (less than 2% chance per year for the progesterone IUD, less than 1% chance per year for the copper IUD). IUDs come with increased risk of ectopic pregnancy and perforation of the uterus and do not protect against sexually transmitted disease. IUDs are prescribed and placed by health care providers.

The female reproductive system includes the vagina, cervix, and uterus shown here in cut section.

The pill works in several ways to prevent pregnancy. The pill suppresses ovulation so that an egg is not released from the ovaries, and changes the cervical mucus, causing it to become thicker and making it more difficult for sperm to swim into the womb. The pill also does not allow the lining of the womb to develop enough to receive and nurture a fertilized egg. This method of birth control offers no protection against sexually-transmitted diseases.

Artificial contraception methods work in different ways to decrease the likelihood that sexual intercourse will result in pregnancy. Barrier methods such as condoms (male or female), diaphragms (with or without spermicide) and sponges (with spermicide) have as their first line of defense the physical blocking of the sperm’s entry into the uterus. If sperm cannot get into the uterus it cannot fertilize an egg, and pregnancy cannot occur. IUDs disrupt the normal uterine environment. The hormones in oral contraceptives and hormone implants fool the ovaries into refraining from ovulation, and without a fertile egg, pregnancy will not occur. IUDs and oral contraceptives and hormones may be used as emergency contraception in the case of unprotected sex, but neither one will protect against sexually-transmitted disease.

Information

Emergency contraception most likely prevents pregnancy in the same way as regular birth control pills:

• By preventing or delaying the release of an egg from a woman’s ovaries
• By preventing the sperm from fertilizing the egg

The two ways you may receive emergency contraception are by:

• Using pills that contain a man-made (synthetic) form of the hormone progesterone called progestins. This is the most common method.
• Having an IUD placed inside the uterus.

CHOICES FOR EMERGENCY CONTRACEPTION

Two emergency contraceptive pills may be bought without a prescription.

• Plan B One-Step is a single tablet.
• Next Choice is taken as 2 doses. Both pills can be taken at the same time or as 2 separate doses 12 hours apart.
• Either may be taken for up to 5 days after unprotected intercourse.

Ulipristal acetate (Ella) is a new type of emergency contraception pill. You will need a prescription from a health care provider.

• Ulipristal is taken as a single tablet.
• It may be taken up to 5 days after unprotected sex.

Birth control pills may also be used:

• Talk to your provider about the correct dosage.
• In general, you must take 2 to 5 birth control pills at the same time to have the same protection.

IUD placement is another option:

• It must be inserted by your provider within 5 days of having unprotected sex. The IUD that is used contains a small amount of copper.
• Your provider can remove it after your next period. You may also choose to leave it in place to provide ongoing birth control.

MORE ABOUT EMERGENCY CONTRACEPTIVE PILLS

Women of any age can buy Plan B One-Step and Next Choice at a pharmacy without a prescription or visit to a provider.

Emergency contraception works best when you use it within 24 hours of having sex. However, it may still prevent pregnancy for up to 5 days after you first had sex.

You should not use emergency contraception if:

• You think you have been pregnant for several days.
• You have vaginal bleeding for an unknown reason (talk to your provider first).

Emergency contraception may cause side effects. Most are mild. They may include:

• Changes in menstrual bleeding
• Fatigue
• Headache
• Nausea and vomiting

After you use emergency contraception, your next menstrual cycle may start earlier or later than usual. Your menstrual flow may be lighter or heavier than usual.

• Most women get their next period within 7 days of the expected date.
• If you do not get your period within 3 weeks after taking emergency contraception, you might be pregnant. Contact your provider.

Sometimes, emergency contraception does not work. However, research suggests that emergency contraceptives have no long-term effects on the pregnancy or developing baby.

OTHER IMPORTANT FACTS

You may be able to use emergency contraception even if you cannot regularly take birth control pills. Talk to your provider about your options.

Emergency contraception should not be used as a routine birth control method. It does not work as well as most types of birth control.

References

Allen RH, Huguenin A, Hickey M, Kaunitz AM. Hormonal contraception. In: Melmed S, Auchus RJ, Goldfine AB, Rosen CJ, Kopp PA, eds. Williams Textbook of Endocrinology. 15th ed. Philadelphia, PA: Elsevier; 2025:chap 16.

Rivlin K, Davis AR. Contraception and abortion. In: Gershenson DM, Lentz GM, Valea FA, Lobo RA, eds. Comprehensive Gynecology. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 13.

Winikoff B, Grossman D. Contraception. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 220.

Version Info

Last reviewed on: 3/31/2024

Reviewed by: LaQuita Martinez, MD, Department of Obstetrics and Gynecology, Emory Johns Creek Hospital, Alpharetta, GA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.