Plan B is a form of emergency contraception designed to prevent pregnancy after unprotected sexual intercourse or when other birth control methods have failed. It serves as a backup option and is not intended for routine use as a primary method of birth control.
Understanding the Critical Timeframe
Plan B, which contains the hormone levonorgestrel, is most effective when taken as soon as possible after unprotected sex. The medication is generally recommended for use within 72 hours of the incident. While its effectiveness is highest during this initial window, it can still offer some protection if taken up to 120 hours later.
The effectiveness of Plan B significantly decreases with each passing day. For instance, studies indicate it can be around 94% effective within the first 24 hours, but this drops to approximately 58% when taken within 72 hours. The timing is crucial because the pill primarily works by interfering with the body’s natural ovulation process. Waiting longer increases the likelihood that ovulation may have already occurred, diminishing the pill’s ability to prevent pregnancy.
How Plan B Works
Plan B works primarily by delaying or preventing ovulation, which is the release of an egg from the ovary. The active ingredient, levonorgestrel, is a synthetic form of progesterone that delivers a high dose of this hormone to temporarily disrupt the natural hormonal signals that trigger ovulation. If an egg is not released, there is no egg available for sperm to fertilize, thereby preventing pregnancy.
It is important to understand that Plan B is not an abortion pill and does not terminate an existing pregnancy. The medication will not work if a fertilized egg has already implanted in the uterus. Plan B acts before pregnancy is established, making it a form of contraception rather than an abortifacient.
What to Expect and Next Steps
After taking Plan B, individuals may experience some temporary side effects, which are generally mild. Common reactions can include nausea, abdominal pain, fatigue, headache, and breast tenderness. Changes to the menstrual cycle are also typical, with the next period potentially being earlier, later, heavier, or lighter than usual.
If vomiting occurs within two hours of taking the pill, it is advisable to consult a healthcare professional, as another dose might be necessary to ensure effectiveness. Medical advice should also be sought if the next period is more than a week late, if severe abdominal pain develops, or if there are any concerns about a possible pregnancy. Plan B is available over-the-counter at most pharmacies without a prescription or age restriction.