Emergency contraception is therapy used to prevent pregnancy after unprotected intercourse or contraception failure (ie: condom breaking). There are two oral emergency contraception regimens; a combined estrogen-progestin regimen and a progestin-only regimen, marketed as “Plan B One-Step” in the U.S. Plan B One-Step consists of 2 pills of a progesterone hormone called levonorgestrel. When Plan B was initially introduced in these pills were taken twelve hours apart, but since 2009, Plan B One-Step has replaced the original regimen. In the One-Step regimen, both pills are taken together at once. Emergency contraception is most effective at preventing pregnancy when taken within 72 hours or 3 days of unprotected intercourse, and can prevent up to 89% of unintended pregnancies. Emergency contraception is most effective the earlier it is taken after unprotected intercourse, but can be used up to 5 days after unprotected intercourse to prevent pregnancy .
Plan B One-Step is available over the counter in the U.S., but must be dispensed by the pharmacist and requires proof of age (ie: driver’s license) for purchase. It is available without a prescription to women age 17 years or older. Anyone who is under age 17 requires a doctor’s prescription to obtain Plan B One-Step. The over the counter cost is approximately $50.
Oral emergency contraception regimens like Plan B do delay ovulation, but there is no single method of action to prevent pregnancy. Plan B does not terminate or abort an already established pregnancy.
Common side effects of oral emergency contraception include nausea and vomiting, irregular bleeding, breast tenderness, dizziness, headache and fatigue.
After emergency contraception use, the menstrual period usually occurs within 1 week before or after the expected time. Some women will experience irregular bleeding or spotting the week after the oral emergency contraception regimen is taken. If your period is more than a week late after using emergency contraception, keep in mind that you could be pregnant. If you do become pregnant after using emergency contraception, there is no risk to your baby. However, as with any pregnancy, it is important to see your doctor to confirm a normally developing intrauterine pregnancy. You may also want to consult with your doctor regarding ongoing reliable contraception options.
Remember that emergency contraception does not protect against sexually transmitted diseases.
Another less-well known form of emergency contraception is the copper or “Paragard” intrauterine device (IUD). The copper IUD may be placed within 5 days of unprotected intercourse and act as both emergency and long-term contraception. The progesterone or “Mirena” IUD is not effective for emergency contraception.