If you forget to use birth control or your usual method has failed, emergency contraception can prevent pregnancy after you've already had sex.
Emergency contraception works because the fertilization of an egg by the sperm doesn't happen right at the time of the intercourse. In fact, it can happen up to two or three days later. Emergency contraceptives work by preventing fertilization and implantation, just like other contraceptives. But they don't stop a pregnancy that is already in progress. That is why it is important to use emergency contraception as soon as possible after intercourse.
Emergency contraception is designed as a "last-chance" measure, and it's only about 90% effective. It also can't protect you from sexually transmitted diseases. But, while it isn't meant to be relied upon as your primary method of birth control, it is an effective backup in circumstances such as the following:
- You had sex and used no other form of birth control.
- Your usual form of birth control failed - the condom broke or slipped, your diaphragm slipped out of place or was removed too soon after sex, or you missed 2 or more birth control pills.
- You were on medication that may interfere with your oral contraceptives.
- You were sexually assaulted.
Depending on how long it has been since you had unprotected sex, there is more than one option for emergency contraception. The better-known method is hormonal, which is most effective within 72 hours of unprotected sex and involves taking pills. These pills contain the same ingredients as regular birth control pills, but in higher strength.
Emergency contraception medication is available in three forms:
- Ovral®, a birth control pill, is available as a prescription for 4 tablets from your doctor. If you have a drug plan that pays for your prescriptions and you want the medication to be eligible for reimbursement, a prescription will be required. This option is a little less convenient, as it involves consuming more tablets and is associated with more side effects, such as nausea and vomiting.
- There is also a product called Plan B® available without prescription at the dispensary counter in your local pharmacy. This option involves taking 2 tablets, either together at the same time, or one tablet followed by the second exactly 12 hours later. Nausea and vomiting are less common with this method.
- With both methods of oral emergency contraception, your menstrual cycle may be altered a bit (periods may come earlier or later and be heavier or lighter; they may also experience some spotting); however, a regular menstrual cycle should still be expected at the normal time. If a period does not come within 2 to 3 weeks after taking oral emergency contraception, you should do a pregnancy test or see your doctor immediately.
- If you've left it beyond the 72-hour window, there is still the option of inserting an IUD (intrauterine device), which prevents a fertilized egg from implanting itself in the uterus, and is effective up to a week after intercourse.