How long do the side effects of Ella last?

October 10, 2025 •

3 min read

Ella is an emergency contraceptive that can lower the chances of pregnancy by up to 98% if taken within 5 days of unprotected sex. Understanding the duration of its side effects is crucial; find out how long do the side effects of Ella last and how to manage them.

Quick Summary

Most side effects from Ella, such as headaches and nausea, are mild and resolve within a few days. Changes to the menstrual cycle may persist until the next period. Severe symptoms are rare but require medical attention.

Key Points

Short-Lived Effects: Most common side effects of Ella, like headache and nausea, typically last only a few days.
Menstrual Changes: Your period may be delayed, on average by about 2.5 days, but should return to normal the next cycle.
When to Test: If your period is more than 7 days late after taking Ella, you should take a pregnancy test.
Vomiting Precaution: If you vomit within 3 hours of taking Ella, contact a healthcare provider as you may need another dose.
Severe Pain is a Warning: Seek immediate medical attention for severe lower abdominal pain 3-5 weeks after taking Ella, as it could be a sign of an ectopic pregnancy.
Managing Symptoms: Mild side effects like cramps and headaches can often be managed at home with rest and over-the-counter pain relievers.
Effectiveness Window: Ella is an emergency contraceptive that can be used up to 5 days (120 hours) after unprotected sex.

What is Ella and How Does It Work?

Ella is a prescription emergency contraceptive pill containing ulipristal acetate. It is used to prevent pregnancy after unprotected sex or contraceptive failure and can be taken up to 120 hours (5 days) later. Ella works mainly by preventing or delaying ovulation. Since fertility returns quickly, using a barrier method like condoms until your next period is recommended. Ella does not end an existing pregnancy.

Common Side Effects of Ella and Their Typical Duration

Most side effects of Ella are mild and temporary, usually lasting a few hours to a few days. Up to 1 in 10 people may experience these.

Headache, Dizziness, and Fatigue

Headaches are a common side effect. Dizziness and tiredness are also frequently reported. These effects are generally mild and resolve relatively quickly. Rest and hydration can help.

Nausea and Abdominal Pain

Nausea, stomach pain, and menstrual-like cramps are common. These should subside on their own, but severe or prolonged pain (more than two days) warrants medical advice. Taking Ella with food may help nausea. If you vomit within 3 hours of taking the pill, contact a healthcare provider as you may need another dose.

Changes to Your Menstrual Cycle

Ella can affect your next period, potentially making it a few days earlier or later. The average delay in studies was about 2.5 days. Spotting between periods is also possible and typically resolves with the next cycle. If your period is over a week late, take a pregnancy test.

Less Common and More Severe Side Effects

Though rare, some side effects are more serious and require immediate medical attention.

Allergic Reactions: Symptoms like hives, difficulty breathing, or facial swelling indicate a severe allergic reaction.
Ectopic Pregnancy: Severe lower abdominal pain, particularly on one side, 3 to 5 weeks after taking Ella could signal an ectopic pregnancy, which is an emergency.
Other Less Common Effects: These can include mood swings, muscle pain, back pain, and breast tenderness, affecting up to 1 in 100 people.

Comparison Table: Ella (Ulipristal Acetate) vs. Plan B (Levonorgestrel)

Both are emergency contraceptives with similar, usually mild, short-lived side effect profiles.


Feature / Side Effect	Ella (Ulipristal Acetate)	Plan B (Levonorgestrel) & Generics
Active Ingredient	Ulipristal Acetate	Levonorgestrel
Effective Window	Up to 120 hours (5 days)	Most effective within 72 hours (3 days)
Prescription Needed	Yes	No, available over-the-counter
Common Side Effects	Headache, nausea, abdominal pain, menstrual changes, dizziness, fatigue	Similar to Ella: Nausea, abdominal pain, fatigue, headache, menstrual changes
Impact of Weight	Effectiveness is generally maintained at higher BMIs compared to levonorgestrel.	Research suggests it may be less effective in people heavier than 165 pounds.

How to Manage Ella's Side Effects at Home

For mild side effects, at-home care can help.

For Pain and Headaches: Over-the-counter pain relievers like ibuprofen or acetaminophen can be used.
For Nausea: Taking the pill with food, eating small meals, and avoiding greasy or spicy foods may help.
For Cramps: A heating pad can provide relief.
For Dizziness and Fatigue: Rest and hydration are key. Avoid alcohol.

When to Contact a Healthcare Provider

Contact a doctor or seek emergency care if you experience:

Signs of an allergic reaction.
Severe abdominal pain 3 to 5 weeks after taking Ella.
Vomiting within 3 hours of taking the dose.
A period delay of more than one week.
Severe, unmanageable, or persistent side effects.

Conclusion

Ella's side effects are generally mild and short-lived, typically resolving within a few days. Changes to the menstrual period are the most common lingering effect, usually normalizing by the next cycle. While severe issues are rare, recognizing warning signs like severe abdominal pain is crucial. Consult a healthcare provider for any concerns about side effects or a significantly delayed period.

For more details, refer to the FDA-approved patient information for Ella.

Read the FDA Patient Information for Ella

Frequently Asked Questions

The most common side effects of Ella are headache, nausea, and abdominal or stomach pain. Other common side effects include menstrual pain, tiredness, and dizziness.

Ella can delay your period by a few days. In clinical trials, the average delay was 2.5 days. However, if your period is more than 7 days late, you should take a pregnancy test.

It's possible to experience spotting or breakthrough bleeding after taking Ella. Your next period might also be heavier or lighter than normal. This is usually not a cause for concern unless the bleeding is very heavy.

Headaches from Ella are typically mild and should go away on their own within a day or two. Rest and staying hydrated can help.

You should see a doctor if your side effects are severe, last longer than a few days, or if you experience severe lower stomach pain 3 to 5 weeks after taking it. Also, consult a doctor if your period is more than a week late.

Repeated use of Ella within the same menstrual cycle is not recommended, as its safety and effectiveness have not been evaluated for such use.

The only way to know for sure that Ella has worked is when you get your next period. If your period is more than 7 days late, you should take a pregnancy test.