Morning After Pill Side Effects: What to Expect and When to Call Your Doctor

After taking the morning after pill—whether Plan B, a generic levonorgestrel product, or ella—it is normal to experience some side effects. The good news is that most side effects are mild and short-lived. Millions of people have taken emergency contraception without serious complications. Here is exactly what to expect and when you need to contact a healthcare provider.

Common Side Effects of Plan B and Generic Levonorgestrel

The most common side effects of levonorgestrel emergency contraception (Plan B, My Way, Take Action, etc.) include:

• Nausea: One of the most reported side effects. Taking Plan B with food may help. If you vomit within 2 hours of taking the pill, contact your provider—you may need to take another dose.
• Headache: Mild headaches are common in the hours after taking emergency contraception and typically resolve on their own.
• Dizziness or lightheadedness: May occur for a few hours after taking the pill. Avoid driving if you feel dizzy.
• Breast tenderness: Temporary breast soreness or sensitivity may occur due to the hormone surge.
• Abdominal cramping: Mild cramping is normal and usually resolves within a day or two.
• Fatigue: Feeling tired or run-down after taking emergency contraception is common.

What Happens to Your Period After Emergency Contraception?

Changes to your menstrual cycle are one of the most common effects of emergency contraception, and they are entirely expected:

• Your next period may come earlier or later than usual—sometimes by a week or more
• Your period may be heavier, lighter, or more spotty than usual
• Spotting or irregular bleeding between when you took the pill and when your period arrives is common
• In studies, periods were delayed by about 2–3 days on average after taking ella (ulipristal acetate)

Your menstrual cycle should return to its normal pattern within 1–2 months. If it does not, discuss this with a healthcare provider.

Side Effects of Ella (Ulipristal Acetate)

The side effects of ella are similar to those of levonorgestrel but with some differences. Common ella side effects include headache, nausea, abdominal pain, fatigue, and delayed menstrual period. If you vomit within 3 hours of taking ella (compared to 2 hours for Plan B), contact your provider about potentially repeating the dose.

One important additional note for ella: avoid eating grapefruit or drinking grapefruit juice while taking ella, as it may interact with the medication.

When to Call Your Doctor After Taking Emergency Contraception

While serious complications are rare, contact your healthcare provider if you experience:

• Severe lower abdominal pain (especially on one side) 3–5 weeks after taking emergency contraception. This could be a sign of ectopic pregnancy—a fertilized egg implanted outside the uterus. Seek emergency care immediately.
• Heavy bleeding soaking a pad every hour for 2 hours or longer. Some spotting is normal; heavy, prolonged bleeding is not.
• No period within 3 weeks of taking emergency contraception. Take a home pregnancy test to rule out pregnancy. A late period alone is a common and expected side effect, but if it's more than 3 weeks late, confirm with a test.
• Signs of allergic reaction: Trouble breathing, rash, hives, or swelling of face/throat. Seek emergency care.

Does the Morning After Pill Affect Fertility?

No. Emergency contraceptive pills do not affect long-term fertility. Fertility returns to normal very quickly after taking the pill—in fact, one reason regular ongoing contraception is recommended promptly after using EC is that fertility can return within days.

There is no evidence that taking emergency contraception—even multiple times—causes infertility. Studies of women who used levonorgestrel EC multiple times found no adverse effects on future fertility.

For information about drug interactions, see morning after pill drug interactions. Need to find it in stock near you? medfinder calls pharmacies to check stock on your behalf.