Plan B One-Step

Plan B One-Step also is referred to as the morning-after pill. It is intended to prevent pregnancy after a known or suspected contraceptive failure, unprotected intercourse, or forced sex. It contains large amounts of levonorgestrel, a progestin hormone found in some birth control pills. Plan B One-Step may work by preventing the egg and sperm from meeting by delaying ovulation. It won’t disrupt an implanted pregnancy, but may prevent a newly formed life from implanting in the uterus.[1]

Plan B One-Step consists of one pill taken up to 72 hours after sex.[2] Side effects may include changes in your period, nausea, lower abdominal pain, fatigue, headache, and dizziness.[3] If your period is more than a week late, you may be pregnant from a prior sexual encounter. Plan B One-Step should not be taken during pregnancy or used as a routine form of birth control.[4]

There is evidence Plan B One-Step use may increase the risk for ectopic (tubal) pregnancy, a potentially life-threatening condition.[5] Women who have severe abdominal pain may have an ectopic (tubal) pregnancy, and should seek immediate medical attention.

It is reported Plan B One-Step may prevent an average of 84% of expected pregnancies.[6]

There is much that is unknown about Plan B One-Step including the following: