Emergency Birth Control: Morning-After Pill vs Ella vs IUD, Compared

If you've had unprotected sex or a contraception failure, such as a broken condom, missed birth control pills, or a late Depo shot, emergency birth control can help prevent pregnancy. The important part is timing. Some options work best within 3 days, while others remain effective for up to 5 days after sex.

In the US, the three main options are Plan B and its generic versions (levonorgestrel), Ella (ulipristal acetate), and the copper IUD. They are not interchangeable. They differ in how well they work, how quickly you can get them, and whether they provide ongoing contraception.

The copper IUD is the most effective emergency contraception option, with pregnancy prevention exceeding 99% when inserted within the recommended window. Ella is generally more effective than Plan B between 3 and 5 days after sex. Plan B is available over the counter, making it one of the easiest options to access quickly.

Weight may also affect how well emergency contraceptive pills work, although there is no exact weight at which either pill suddenly stops working. The copper IUD is not known to lose effectiveness because of body weight.

Here's how morning-after pill vs Ella vs IUD compares, including timing, access, side effects, and what to consider when choosing emergency contraception.

TL;DR: Key Takeaways

• Plan B: Over-the-counter levonorgestrel. Take it as soon as possible. It works best within 72 hours, although it may still reduce pregnancy risk through day 5, with effectiveness declining over time.
• Ella: Prescription ulipristal acetate. It is approved for use up to 120 hours (5 days) and is generally more effective than Plan B later in that window.
• Copper IUD: The most effective emergency contraception, with more than 99% effectiveness when inserted within the recommended timeframe. It also provides ongoing birth control.
• Weight matters: Oral emergency contraception may be less effective at higher body weights, particularly levonorgestrel. The evidence does not support treating 165 or 195 pounds as absolute cutoffs.
• Act promptly: Emergency contraception works best when used as soon as possible.
• Access differs: Plan B is available without a prescription, Ella requires one, and a copper IUD must be inserted by a clinician.
• Emergency contraception helps prevent pregnancy after unprotected sex. It does not terminate an established pregnancy or protect against sexually transmitted infections.

Need Ella (ulipristal acetate) within the 5-day window? Book a $39 online urgent care visit with August AI. A US-licensed clinician can review your situation and prescribe Ella if clinically appropriate. Pharmacy availability and pickup timing vary. The visit does not guarantee a prescription, and medication costs are separate. For a copper IUD, contact an OB-GYN, women's health clinic, or Planned Parenthood to ask about timely insertion.

The three options: how they actually differ

Emergency contraception is used after sex to reduce the chance of pregnancy. The method that makes sense for you depends on how much time has passed, your medications, your preferences, and whether you want ongoing contraception.

The CDC notes that Ella and levonorgestrel have similar effectiveness during the first 3 days, while Ella has been observed to work better between days 3 and 5. The copper IUD is highly effective and can remain in place as regular contraception.

The difference: Plan B is easiest to obtain without a prescription, Ella is generally the more effective oral option later in the 5-day window, and the copper IUD provides the highest effectiveness plus ongoing pregnancy prevention.

Plan B (morning-after pill): the over-the-counter option

Plan B and generic levonorgestrel products, including Take Action, My Way, and other store-brand versions, are widely available without a prescription in the US.

Levonorgestrel primarily works by delaying or preventing ovulation. If ovulation has already happened, it may not prevent pregnancy. It does not end an existing pregnancy.

Plan B should be taken as soon as possible after unprotected sex or contraceptive failure.

• Within 24 hours: Take it promptly. Earlier use generally improves the chance of preventing pregnancy.
• 24-72 hours: It can still work, but effectiveness decreases with time.
• After 72 hours: Ella or a copper IUD is generally preferred. Levonorgestrel may still reduce pregnancy risk through day 5, but it is less effective when taken later, particularly on days 4-5.

The exact chance of preventing pregnancy depends on when sex occurred in relation to ovulation and other individual factors. A simple 89% or 75% figure cannot reliably predict whether it will work for one person.

What about weight?

Research suggests levonorgestrel emergency contraception may be less effective at higher body weights, particularly in people with obesity. Some discussions use 165 pounds or 176 pounds as reference points, but these are not firm thresholds where the pill suddenly stops working.

If Plan B is the only option you can access quickly, taking it is generally preferable to delaying emergency contraception while trying to find another method. If you can access Ella or a copper IUD promptly, discuss those options with a clinician.

• Need an option without a prescription.
• Can get it immediately at a pharmacy.
• Are within the first 72 hours.
• Prefer not to have an IUD inserted.
• Cannot access a clinician quickly.

• Are already 3-5 days past sex.
• Have a higher body weight and can access Ella or a copper IUD.
• Take medications that may reduce levonorgestrel effectiveness.
• Want ongoing contraception from an IUD.

Ella (ulipristal acetate): the prescription option

Ella is a prescription emergency contraceptive containing 30 mg of ulipristal acetate. It is approved for use up to 120 hours, or 5 days, after unprotected sex or contraceptive failure.

Ella acts on progesterone receptors and delays ovulation. It can delay ovulation closer to the time it would otherwise occur than levonorgestrel can. Like Plan B, it does not terminate an established pregnancy.

• It can be used through 120 hours after sex.
• It has shown greater effectiveness than levonorgestrel during days 3-5.
• It may be a better oral option than levonorgestrel for some people with higher body weight, although the evidence does not establish a precise weight cutoff.
• It can delay ovulation later in the ovulation process than levonorgestrel.

Ella is not guaranteed to work, and it cannot reliably prevent pregnancy if ovulation has already occurred.

Some studies suggest Ella may be less effective at higher BMI levels, but the evidence is limited and does not establish a reliable cutoff such as 195 pounds. The copper IUD remains the most effective emergency contraception option regardless of weight.

If you have a higher body weight, ask a clinician about Ella and the copper IUD rather than assuming an oral option will not work.

• A prescription is required in the US.
• A telehealth clinician may be able to evaluate you and prescribe it when appropriate.
• Pharmacy stock varies. Call ahead if timing is important.
• Do not wait for a prescription appointment if an over-the-counter option is the only method you can access immediately.

Ella has a few instructions that matter after taking it:

• Wait at least 5 days before starting or restarting hormonal birth control.
• Use condoms or avoid sex while waiting to restart hormonal birth control. After restarting, follow your method's instructions for how long backup contraception is needed.
• Certain medications, including some anti-seizure medicines and drugs that affect liver enzymes, can reduce Ella's effectiveness.
• If you vomit within 3 hours of taking Ella, contact a clinician or pharmacist because another dose may be needed.

The FDA-approved prescribing information specifically recommends waiting at least 5 days before restarting hormonal contraception because progestin may interfere with Ella's ability to delay ovulation.

Ella side effects

Common short-term side effects of emergency contraceptive pills can include nausea, headache, abdominal pain or cramping, fatigue, dizziness, breast tenderness, and changes in the timing or amount of your next period.

For guidance on ongoing birth control options after emergency contraception, see our guide on is Sprintec a good birth control? What 1,000+ reviews and the FDA label actually show.

Copper IUD (Paragard): the most effective option

The copper IUD is the most effective established emergency contraception method. When inserted within 5 days of unprotected sex, it reduces pregnancy risk by more than 99%. It can also remain in place for ongoing contraception for up to 10 years.

Copper affects sperm movement and function, making fertilization much less likely. The device does not contain hormones.

• More than 99% effective as emergency contraception when placed within the recommended window.
• Not known to be affected by body weight or BMI.
• Ongoing contraception for up to 10 years with Paragard.
• Hormone-free, which may suit people who prefer non-hormonal birth control.
• Immediate contraceptive protection after insertion, with no backup method required for pregnancy prevention.

• A clinician must insert it.
• Placement may cause cramping or discomfort.
• Periods may become heavier or more painful, particularly during the first few months.
• Cost varies. Insurance coverage and clinic pricing differ.
• Not every clinic has same-day appointments or emergency IUD insertion available.

• Want the most effective emergency contraception.
• Have a higher body weight and want an option not affected by weight.
• Want long-term contraception as well.
• Prefer to avoid hormones.
• Can access a clinic within the recommended time window.

Planned Parenthood, OB-GYN offices, and women's health clinics may offer insertion, but availability varies. Call and specifically ask whether they provide copper IUD placement for emergency contraception.

For guidance on hormonal birth control alternatives to consider after emergency contraception, see our guide on Slynd vs norethindrone: how the two progestin-only pills differ.

Which emergency contraception should you choose?

There is no single option that fits everyone. Use the following as a starting point, not a substitute for individualized advice.

• Need an option immediately without a prescription.
• Are within the first 72 hours.
• Cannot access Ella or a clinic promptly.
• Prefer a pill rather than an IUD.

• Are between 3 and 5 days after unprotected sex.
• Want an oral option that is generally more effective than Plan B later in the window.
• Have a higher body weight and want to discuss oral emergency contraception options.
• Can obtain a prescription and fill it promptly.
• Do not need an IUD for ongoing contraception.

• Want the most effective emergency contraception.
• Want ongoing contraception after the emergency.
• Have a higher body weight.
• Prefer a hormone-free method.
• Can arrange insertion within the recommended window.

If you are unsure which option is available fastest, contact a pharmacist, clinician, or reproductive health clinic and explain how many hours or days have passed. Do not delay an available option while trying to find a theoretically preferred one.

For guidance on managing side effects that may follow hormonal contraception, see our guide on Sprintec side effects: what's normal in the first month, and what isn't.

What emergency contraception won't do

Emergency contraception is useful after sex, but it has limits.

Plan B and Ella work primarily by delaying or preventing ovulation. They are not abortion medications and do not end an established pregnancy. A copper IUD is also not used as emergency contraception when someone is known to be pregnant.

No emergency contraception method is 100% effective. If your period is more than a week later than expected, take a pregnancy test. You can also test about 3 weeks after taking emergency contraception if you have not had a normal period.

Emergency contraceptive pills do not provide ongoing pregnancy protection. If you have sex again after taking one, use condoms or another contraceptive method.

A copper IUD, in contrast, continues to prevent pregnancy after insertion.

Emergency contraception does not protect against sexually transmitted infections, including HIV. Consider STI testing after unprotected sex. If you may have been exposed to HIV, seek urgent medical advice about post-exposure prophylaxis (PEP), which must be started within 72 hours.

When to contact a physician

Contact a clinician or pharmacist promptly if:

• You are more than 72 hours past sex and need help accessing Ella or an IUD.
• You take medication that may interact with emergency contraception.
• You vomit within 3 hours of taking Ella or within the timeframe listed on your Plan B product instructions.
• You are unsure whether to restart your regular hormonal birth control.
• You want an IUD but cannot find a clinic with timely insertion.

• Your period is more than a week late.
• You have not had a normal period within 3 weeks after emergency contraception.
• You have a positive pregnancy test.
• You have persistent or concerning side effects.

Seek urgent in-person care for severe or one-sided lower abdominal pain, fainting, or heavy bleeding, especially if pregnancy is possible. These symptoms need evaluation, including for ectopic pregnancy.

To track your prescriptions and health records for future reference, see our guide on how to view your medical records online for free.

The Bottom Line

The three main emergency contraception options in the US have different strengths.

• Plan B: Over-the-counter and easy to access, best taken as soon as possible, particularly within 72 hours.
• Ella: Prescription pill that works up to 5 days and is generally more effective than Plan B later in the window.
• Copper IUD: More than 99% effective when inserted within the recommended window, not known to be affected by weight, and provides ongoing contraception.

Weight, medication interactions, timing, and access all matter. The numbers sometimes used as weight cutoffs are estimates, not guarantees that a pill will or will not work.

If you need emergency contraception, act as soon as you can. If Ella is the option you are considering, contact a clinician and pharmacy promptly. If you want a copper IUD, ask a reproductive health clinic about emergency insertion availability.

The most useful option is one you can access in time and feel comfortable using.