Plan B Side Effects

February 10th, 2012 by Helen Scholz

Levonorgestrel is a female hormone that prevents ovulation (the release of an egg from an ovary). Plan B also causes changes in your cervical mucus and uterine lining, making it harder for sperm to reach the uterus and harder for a fertilized egg to attach to the uterus.

Plan B is used to prevent pregnancy after unprotected sex or failure of other forms of birth control (such as condom breakage, or missing 2 or more birth control pills).

Plan B may also be used for other purposes not listed in this medication guide.

Get emergency medical help if you have any of these signs of an allergic reaction to Plan B: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have severe pain in your lower stomach or side. This could be a sign of a tubal pregnancy (a pregnancy that implants in the fallopian tube instead of the uterus). A tubal pregnancy is a medical emergency.

Less serious Plan B side effects may include:

• nausea, diarrhea, or stomach pain;
• breast pain or tenderness;
• dizziness, tired feeling;
• changes in your menstrual periods; or
• headache.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.