Plan B is a form of emergency contraception designed to prevent pregnancy after unprotected sex or contraceptive failure. It contains a synthetic hormone and is distinct from an abortion pill, as it works to prevent a pregnancy from occurring rather than ending an existing one. Plan B is not a routine form of birth control.
How Plan B Works and Its Standard Use
Plan B primarily functions by delaying or preventing ovulation, which is the release of an egg from the ovary. The medication contains a high dose of levonorgestrel, which acts by blocking the surge of luteinizing hormone necessary for ovulation. Additionally, levonorgestrel can thicken cervical mucus, making it more difficult for sperm to travel and reach an egg. Plan B is not effective if ovulation has already occurred or if a fertilized egg has already implanted in the uterus. It does not interfere with an established pregnancy.
The standard recommended dosage for Plan B is a single pill containing 1.5 milligrams of levonorgestrel. For maximum effectiveness, this single dose should be taken as soon as possible after unprotected sex, ideally within 72 hours (three days). While it can be taken up to 120 hours (five days) afterward, its effectiveness decreases significantly with time. When taken within the recommended 72-hour window, Plan B can reduce the risk of pregnancy by up to 89%.
Taking More Than One Dose
Taking more than one Plan B pill does not increase its effectiveness in preventing pregnancy. The single-dose formulation is designed to provide the necessary amount of levonorgestrel to delay or prevent ovulation when taken correctly. Doubling the dose is unnecessary and can be counterproductive due to an increased likelihood and severity of side effects.
Taking additional doses beyond the recommended amount can lead to more pronounced side effects. These often include increased nausea, vomiting, dizziness, fatigue, and headaches. A higher dose can also significantly disrupt the menstrual cycle, potentially causing irregular bleeding, periods that are heavier or lighter than usual, or a delay in the next period. While it is generally safe to take Plan B multiple times if separate instances of unprotected sex occur, it is not intended for routine use due to its higher cost and potential for more frequent side effects compared to routine contraception.
What to Do After Taking Plan B
After taking Plan B, individuals may experience various temporary side effects as the body adjusts to the hormonal changes. Common reactions include changes in the menstrual cycle, such as the next period arriving earlier or later, being heavier or lighter, or experiencing spotting. Other possible side effects include nausea, vomiting, abdominal pain, fatigue, headache, and breast tenderness. These symptoms are typically mild and usually resolve within a few days to a month.
To manage potential nausea, taking the pill with food or water may be helpful. If vomiting occurs within two hours of taking Plan B, it is important to contact a healthcare professional, as another dose might be necessary to ensure effectiveness. If a period does not arrive within three weeks of the expected date, or if it is unusually light, a pregnancy test should be taken. For the most accurate results, it is generally recommended to wait at least two weeks after unprotected sex or a missed period before taking a pregnancy test, as Plan B itself does not affect test results.
Individuals should seek medical attention if they experience severe side effects, persistent or heavy bleeding, or severe abdominal pain, as these could indicate a more serious condition like an ectopic pregnancy. Plan B does not offer protection against sexually transmitted infections (STIs). For ongoing pregnancy prevention, discussing regular birth control options with a healthcare provider is recommended, as unprotected sex after taking the pill can still result in pregnancy.