- The most common Plan B side effects are fatigue, nausea, and pelvic pain.
- There may be changes in your period, such as irregular bleeding.
- Side effects shouldn’t last more than a few days — if they do, talk to your doctor.
- For more information, visit Insider’s Health Reference Library.
Plan B, an over-the counter emergency contraceptive, should be used within 72 hours. Emergency contraceptives come in many brands including Plan B One-Step, Aftera, Econtra EZ, Take Action, Preventeza, and more.
Here are the side effects of taking a Plan-B pill.
The side effects of Plan B
The way emergency contraceptives work is that they contain a large dose of levonorgestrel. Levonorgestrel (a synthetic hormone) is designed to mimic the sex hormone progesterone. It prevents ovulation, and thus, pregnancy.
Plan B and other emergency contraceptives contain 1.5 milligrams of levonorgestrel. That’s three times more than what you get in a regular
birth control
pill. As a result, this large, concentrated dose can cause side effects like:
- Fatigue
- Nausea
- Pelvic pain
- You might also notice changes to your menstrual cycle, like irregular bleeding.
Less common side effects include:
- Vomiting
- Headaches
- Breast tenderness
While plan B side effects can be uncomfortable, they shouldn’t feel excessively extreme or severe. The most serious side effects of plan B should include pelvic pain and disruptions in your cycle.
You should consult a doctor if side effects persist beyond these symptoms or worsen over time. If you are experiencing irregularities in your periods that persist for more than one cycle or if they worsen after a few days, consider a pregnancy test.
How long Plan B side effects last
“The duration of side effects is variable from woman to woman,” says Nina Carroll, MD and OB-GYN of Your Doctors Online. Here’s what Plan B could look like.
- Day 1: After taking the pill, you may experience mild side effects like nausea, vomiting, and pelvic pain. Some people may vomit after taking the pill. It is important to retake your pill in this situation to ensure its effectiveness.
- Days 2 and 3: Symptoms may continue over the course of days two and three.
- Day 4: Most people will no longer experience the side effects of taking a Plan B after four days of using the pill.
- Days or weeks later: Menstrual changes are a common experience for its users and the symptoms may not show up until a woman’s next menstrual cycle, which may be anywhere from days or even weeks after taking the pill.
How to relieve Plan B side effects
Unfortunately, there’s nothing you can do to make the side effects resolve more quickly or prevent them from happening in the first place.
You may be able manage your symptoms. To reduce your discomfort, doctors may recommend an anti-nausea medication or pain relief.
Insider’s takeaway
Plan B side effects shouldn’t last more than four days, however, some women experience changes to their period which may last one menstrual cycle. You may experience nausea or vomiting within the first two hours after taking the pill. This is likely to be a sign that your body has not absorbed levonorgestrel. In this case, you will need another plan B.
Plan B should not serve as regular birth control. It should only be used for emergency situations. Unprotected, ejaculatory sexual activity when you and your partner aren’t on birth control.