Plan B Emergency Contraceptive

Plan B –  Emergency Contraceptive / Morning After Pill

What is Plan B?

The “Morning After Pill” is a common name for the most popular type of emergency contraceptive. Emergency contraceptives or emergency birth control (EC) is used to reduce the chance of a woman getting pregnant after she has had sex without using birth control, during the fertile days while using natural family planning, or if the birth control method failed. While some EC methods may be taken as much as 3-5 days after unprotected sex, EC is most effective when taken as soon as possible (i.e. within a few hours).

Plan B Emergency Contraceptive

Plan B Emergency Contraceptive

There are several brands of emergency contraceptive pills made with a drug named levonorgestrel, including: Fallback Solo, Next Choice, Opcicon, Plan B One Step and other generic brands. Plan B One Step (Plan B) is one of the most commonly recognized brand names.

Plan B is a back-up oral contraceptive method to be used as soon as possible, but no more than three days (72 hours), after unprotected sex or contraception failure, to reduce the chance of pregnancy. Emergency contraceptives do not protect against HIV or other sexually transmitted diseases. Plan B and generic emergency contraceptive pills containing progestin only are available over-the-counter without a prescription.

How does it work?

Levonorgestrel is a hormone known as a progestin. Brands such as Plan B contain this hormone at a higher dose than birth control pills. The main function of levonorgestrel is to prevent or delay ovulation (i.e. to stop the egg from releasing), to block fertilization of the egg, or to prevent the egg from attaching (implantation) to the wall of the uterus (womb). The latest scientific research shows that FDA approved ECPs containing levonorgestrel or ulipristal acetate do not inhibit the implantation of a fertilized egg. ECPs stop pregnancy by keeping the egg from leaving the ovary or keeping the sperm from joining the egg. Plan B will not stop or harm an embryo that has already implanted. If you are already pregnant, emergency contraception will not work. It is not the abortion pill.

Plan B can be used more than once during the month. However, it is not an effective regular birth control method to prevent pregnancy because it does not provide lasting protection. Plan B works before ovulation occurs so if you have unprotected sex after ovulation, taking Plan B may not stop a pregnancy. If you have unprotected sex in the days or weeks after the use of Plan B, there is a risk of becoming pregnant.

Are there side effects?

Side effects of the emergency contraceptive pill may include nausea and vomiting, abdominal pain or cramps, breast tenderness, headache, dizziness, and fatigue (tiredness). Your period may be delayed, come sooner, be heavier or lighter than normal. These side effects usually do not occur for more than a few days after taking the medication. If vomiting occurs within two hours of taking the pill, contact your doctor to see if you need to repeat the dose. If your period is more than one week late, you may be pregnant.

Important: If you become pregnant or experience severe abdominal pain and/or bleeding 3-5 weeks after taking the emergency contraceptive pill, you may have an ectopic pregnancy (the egg has implanted outside the uterus). Since ectopic pregnancies may be life threatening, you should seek immediate medical attention.

How do I know if I should be concerned?

You should be concerned about an unintended pregnancy if you had sex and your birth control failed (i.e. condom broke, diaphragm not inserted correctly, during the fertile days while using natural family planning, etc.), if you did not use contraception, or if you missed/forgot to take your birth control pill(s). If you had sex and think that you may be at risk of pregnancy, chat with our nurse online or schedule an appointment at one of our three Bay Area Support Circle clinics in Oakland, Redwood City, and San Francisco. Support Circle offers free pregnancy tests and same day appointments.

Support Circle provides information about but is not a provider of the morning after pill.

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Morning After Pill

Ella – Emergency Contraceptive



  1. http://www.planbonestep.com/
  2. http://ec.princeton.edu/info/ecp.html