If you have questions about emergency contraception, you’re not alone. What makes it different from other forms of birth control? If you need it, how quickly do you have to take it? How easy is it to get? Is the morning-after pill bad for you? What emergency contraception can you use if you’re breastfeeding? And can emergency contraceptive pills cause infertility?
Of course, it’s best to consult your doctor if you’re concerned about medical issues or how emergency contraception may affect your health. Here, we take a closer look at different types of emergency contraception currently available in the U.S. (yes, several types exist!). We also share lots of detailed information we’ve collected about each method, along with information about research being done on them. Keep in mind that rules and accessibility around emergency contraception vary, so be sure to check your local regulations if you’re considering any of these options.
Table of Contents
- 1. What types of emergency contraception exist?
- 2. Should you stock up on emergency contraception, just in case?
- 3. Does emergency contraception expire?
- 4. Does emergency contraception work during ovulation?
- 5. Will you experience any side effects after using emergency contraception?
- 6. Can emergency contraceptive pills cause infertility?
- 7. Does your weight influence the effectiveness of emergency contraception?
- 8. Can you take emergency contraception while on the pill?
- 9. Can you drink alcohol after taking emergency contraception?
- 10. How often can you take emergency contraception pills?
- 11. Are emergency contraception pills considered abortion pills?
- 12. What if you’re pregnant and don’t know it, and take emergency contraception?
- 13. Does emergency contraception prevent sexually transmitted infections (STIs)?
- 14. When should you test for pregnancy after using emergency contraception?
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1. What types of emergency contraception exist?
There are currently two main forms of emergency contraception: orally taken emergency contraceptive pills (ECPs) and intrauterine devices (IUDs).
Choosing a good option for you depends on a variety of factors, including how long it’s been since you’ve had unprotected sex, your body weight, local access to different methods and whether you can get a prescription quickly. You should also keep in mind reported failure rates, or statistics that refer to how often the emergency contraception in question fails in preventing pregnancy. If you’re breastfeeding, it’s a good idea to check with your doctor before taking an ECP, just to be sure you know how it may impact your body. Like we said before, your doctor should always be your go-to resource for medical advice and navigating choices around emergency contraception.
Let’s take a closer look at how different emergency contraception methods work.
Emergency contraceptive pills that contain levonorgestrel
This is the most commonly discussed emergency contraception, sometimes called the morning-after pill. Levonorgestrel is a progestin, and levonorgestrel ECPs that only require taking one pill are available over the counter in the U.S. to anyone of any age.1
Two-pill versions also exist and are often sold behind the pharmacy counter, without a prescription, to people ages 17 and older.1 When taking two pills, you should typically take the second pill 12 hours after the first2 — but make sure to read the instructions for proper usage. With whichever version you choose (one or two pills), take this medication as soon as possible but no later than within 72 hours of having unprotected sex, according to the included instructions.1 Stated failure rates range from 0.6% to 3.1%.2
Emergency contraceptive pills that contain ulipristal acetate
This pill requires a prescription.1 To find a health center that can prescribe it, enter your ZIP code in the Health Resources & Services Administration "Find a Health Center" database. It’s important to take this pill as soon possible, and no later than within 120 hours of having unprotected sex, according to instructions.1 Stated failure rates range from 0.9% to 2.1%.2
Intrauterine device (IUD)
To be used as emergency contraception, a copper IUD must be inserted by a healthcare professional within five days of unprotected sex.3 The World Health Organization reports that the copper IUD is the most effective form of emergency contraception, with a stated failure rate of less than 0.1% when inserted within 120 hours of unprotected sex.2,3
Currently, hormonal IUDs are not used for emergency contraception in the U.S., though some recent studies have explored hormonal IUDs as an option.4 Once inserted, an IUD can serve as a form of long- acting reversible contraception.3,5
2. Should you stock up on emergency contraception, just in case?
This is a tough question to answer because it depends on your situation. Factors to consider before deciding to stock up on ECPs include:
- How quickly you can get an appointment with a healthcare provider
- The number of healthcare facilities and clinics close to you
- Pharmacy accessibility
- Transportation accessibility
- Your age
- Product expiration dates
Emergency contraception is more effective the sooner you use it, which means a trip to your medicine cabinet is preferable to a trip to the pharmacy.
3. Does emergency contraception expire?
ECPs don’t last forever. Be sure to check the expiration date on the box before you take them. If you do stock up on emergency contraception, check the instruction pamphlet for proper storage instructions, which often advise storing pills away from direct sunlight or excess humidity.
4. Does emergency contraception work during ovulation?
It should, but the answer is a little more complex than a simple yes or no. According to The American College of Obstetricians & Gynecologists (ACOG), the way emergency contraception stops pregnancy from occurring in your body is dependent on many variables: the day of your menstrual cycle when sex occurs, the time in your menstrual cycle when you take the emergency contraception, and the type of emergency contraception used.5
According to ACOG, ECPs containing levonorgestrel and ulipristal acetate may inhibit or delay ovulation.5 If you take ECPs containing levonorgestrel before the level of your luteinizing hormone increases, they may delay follicular development.5 If the level of your luteinizing hormone has already started to increase, ulipristal acetate may inhibit follicular rupture.6 Copper IUDs affect sperm viability and function, preventing fertilization.5
5. Will you experience any side effects after using emergency contraception?
Side effects are typically minimal, and many people don’t experience them at all. Spotting after emergency contraception and/or irregular bleeding for the week after taking emergency contraception medication is considered normal.6 If your period usually arrives about the same time every menstrual cycle, your next period may be early or late.6
You may also experience a headache, nausea and vomiting, breast tenderness, abdominal pain, dizziness and/or fatigue.5 If you experience vomiting within two hours of taking an ECP, you’ll need to take it again (talk to your doctor if this is a concern for you).4 If you opt to have an IUD inserted, you may experience cramping, and there is a small risk of perforation of the uterus during the procedure.5 You also may experience increased menstrual pain and bleeding for several months.6
If you have questions about side effects after using emergency contraception, contact a healthcare professional.
6. Can emergency contraceptive pills cause infertility?
No. According to the World Health Organization, emergency contraception does not harm future fertility nor does it delay the return to fertility.4 A 2018 systematic review and meta-analysis looked at 22 studies through 1985 and 2017 that enrolled 14,884 women who discontinued contraception with hopes of getting pregnant.7 The pooled rate of pregnancy was 83.1% within the first year.7 The analysis concluded that contraception, regardless of duration and progestin type, including hormonal methods and IUDs, did not affect fertility.7
Additionally, a 2022 review published in “Contraception” looked at 33 studies of women exposed to ECPs containing levonorgestrel and found no evidence to support that exposure to levonorgestrel emergency contraception “affects fetal development, miscarriage, stillbirth or subsequent menstruations.”8
7. Does your weight influence the effectiveness of emergency contraception?
There’s a chance it might, depending on the form you choose. According to ACOG, if your body mass index (BMI) indicates you are overweight (BMI of 25 to 29.9) or obese (BMI of 30 or greater), it may reduce the effectiveness of levonorgestrel emergency contraception pills, and research suggests obesity may lower the effectiveness of ulipristal acetate.5 However, the efficacy of copper IUDs as emergency contraception is not affected by body weight.5 Talk to your healthcare provider to determine the best option for you.
8. Can you take emergency contraception while on the pill?
According to ACOG, if you take a progestin-only pill (ECPs that contain levonorgestrel), you can resume or start any birth control method right away. Just be sure to use a barrier method of birth control for the next seven days.6 If you use ulipristal acetate, the reports state that you can resume or start a hormonal birth control method after five days. You’ll need to use a barrier method of birth control until your next period.7
9. Can you drink alcohol after taking emergency contraception?
Yes. There is no known loss in efficacy when drinking alcohol after taking ECPs. The National Institute on Alcohol Abuse and Alcoholism doesn’t list any contraceptive methods on its list of commonly used prescription and over-the-counter medicines that interact with alcohol. Although alcohol consumption doesn’t impact the efficacy of emergency contraception, it’s a good idea to talk with your doctor about alcohol consumption and moderation.
10. How often can you take emergency contraception pills?
ACOG advises that you can take emergency contraceptive pills once per menstrual cycle.6 You still shouldn’t rely on emergency contraceptive pills for long-term birth control, but the reason has nothing to do with future fertility.4,7 Rather, emergency contraceptive pills are not as effective at preventing pregnancy as other forms of birth control.7 Instead, think of them as a backup method for emergencies, for cases when your regular method of birth control may have failed. Talk to your healthcare professional to figure out the best long-term method for you.
11. Are emergency contraception pills considered abortion pills?
Scientifically, emergency contraception pills are not considered abortion pills. A medical abortion ends a pregnancy after implantation has occurred5,6 — and emergency contraception does not work after implantation.1,2,4,5 This is why emergency contraception must be used quickly after unprotected sex to be effective.
12. What if you’re pregnant and don’t know it, and take emergency contraception?
Studies have shown that none of the hormonal emergency contraceptive pills available today will harm a pregnancy or the health of the fetus.5 Like we said, emergency contraception does not work if implantation has already occurred.1,2,4,5
13. Does emergency contraception prevent sexually transmitted infections (STIs)?
No. If you had unprotected sex and think you may have been exposed to a sexually transmitted infection (STI), it’s important to see a healthcare professional right away.1 STIs are common and easily spread, and while some can be treated and cured, others cannot.9
You may suspect an STI based on symptoms (like vaginal discharge, pain or irritation, for example), but sometimes there are no symptoms, or symptoms occur only after the infection has been present for quite some time.9 A healthcare provider can test you for STIs to prevent you from passing an infection to others.9 And if you have an STI, early treatment is better.9
14. When should you test for pregnancy after using emergency contraception?
Remember that your period may not arrive at the usual time after using emergency contraception. If you do not get your period within a week of when you expect it, or if you suspect pregnancy, you should take a pregnancy test.1,5 If you think your period is not yet due and you still suspect pregnancy, consider taking an early detection pregnancy test and following the instructions based on when you expected your next period.
Learning more about how emergency contraception methods work, and how they might work for you, is a great way to plan and prepare for the future. Gathering information like this is a good first step, but articles like this one can’t be considered medical advice. As always, a healthcare professional can answer specific questions you might have, so don’t hesitate to reach out for support while making choices about your birth control options.
- Office on Women’s Health, U.S. Department of Health & Human Services. Emergency contraception. Updated January 6, 2023. Accessed January 17, 2023. https://www.womenshealth.gov/a-z-topics/emergency-contraception
- Cleland K, Raymond EG, Westley E, Trussell J. Emergency contraception review: evidence-based recommendations for clinicians. Clin Obstet Gynecol. 2014;57(4):741-750. doi: 10.1097/GRF.0000000000000056. Accessed January 17, 2023. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4216625/
- World Health Organization. Emergency contraception. November 9, 2021. Accessed January 17, 2023. https://www.who.int/news-room/fact-sheets/detail/emergency-contraception
- Turok DK, Gero A, Simmons RG, et al. Levonorgestrel vs. copper intrauterine devices for emergency contraception. N Engl J Med. 2021;384(4):335-344. doi: 10.1056/NEJMoa2022141. Accessed January 17, 2023. https://www.nejm.org/doi/full/10.1056/NEJMoa2022141
- The American College of Obstetricians and Gynecologists. Practice bulletin: emergency contraception. Updated 2022. Accessed January 17, 2023. https://www.acog.org/clinical/clinical-guidance/practice-bulletin/articles/2015/09/emergency-contraception
- The American College of Obstetricians and Gynecologists. Emergency contraception. Updated November 2021. Accessed January 17, 2023. https://www.acog.org/womens-health/faqs/emergency-contraception
- Girum T, Wasie A. Return of fertility after discontinuation of contraception: a systematic review and meta-analysis. Contracept Reprod Med. 2018;3:9. doi: 10.1186/s40834-018-0064-y. Accessed January 17, 2023. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6055351/
- Endler M, Li R, Gemzell Danielsson K. Effect of levonorgestrel emergency contraception on implantation and fertility: a review. Contraception. 2022:109:8-18. doi: 10.1016/j.contraception.2022.01.006. Accessed January 17, 2023. http://www.contraceptionjournal.org/article/S0010-7824(22)00006-3/fulltext
- The American College of Obstetricians and Gynecologists. How to prevent sexually transmitted infections (STIs). August 2020. Accessed January 17, 2023. https://www.acog.org/womens-health/faqs/how-to-prevent-stis
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