Questions and Answers About Emergency Contraceptive Pills
No. ECPs do not work if a woman is already pregnant. When taken before a woman has ovulated, ECPs prevent the release of an egg from the ovary or delay its release by 5 to 7 days. By then, any sperm in the woman's reproductive tract will have died, since sperm can survive there for only about 5 days.
No. Good evidence shows that ECPs will not cause birth defects and will not otherwise harm the fetus if a woman is already pregnant when she takes ECPs or if ECPs fail to prevent pregnancy.
Women who take ECPs should understand that they could become pregnant the next time they have sex unless they begin to use another method of contraception at once. Because ECPs delay ovulation in some women, she may be most fertile soon after taking ECPs. If she wants ongoing protection from pregnancy, she must start using another contraceptive method at once.
Many combined (estrogen-progestin) oral contraceptives and progestin-only pills can be used as ECPs. Any pills containing the hormones used for emergency contraception—levonorgestrel, norgestrel, norethindrone, and these progestins together with estrogen (ethinyl estradiol)—can be used. (See Pill Formulations and Dosing, for examples of what pills can be used.)
Yes. Progestin-only pills contain very small amounts of hormone. Thus, it is necessary to take many pills in order to receive the total ECP dose needed. In contrast, the ECP dosage with combined (estrogen-progestin) oral contraceptives is generally only 2 to 5 pills in each of 2 doses 12 hours apart. Women should not take 40 or 50 combined (estrogen-progestin) oral contraceptive pills as ECPs.
Yes. Women with HIV, AIDS, and those on antiretroviral therapy can safely use ECPs.
Yes. A study of ECP use among girls 13 to 16 years old found it safe. Furthermore, all of the study participants were able to use ECPs correctly.
Yes. This is because ECP treatment is very brief.
No. To date, no evidence suggests that ECPs increase the risk of ectopic pregnancy. Worldwide studies of progestin-only ECPs, including a United States Food and Drug Administration review, have not found higher rates of ectopic pregnancy after ECPs failed than are found among pregnancies generally.
No. Studies of women given ECPs in advance report these findings:
- Women who have ECPs on hand took them sooner after having unprotected sex than women who had to seek out ECPs. Taken sooner, the ECPs are more likely to be effective.
- Women given ECPs ahead of time were more likely to use ECPs than women who had to go to a provider to get ECPs.
- Women continued to use other contraceptive methods as they did before obtaining ECPs in advance.
No. Nearly all other contraceptive methods are more effective in preventing pregnancy. A woman who uses ECPs regularly for contraception is more likely to have an unintended pregnancy than a woman who uses another contraceptive regularly. Still, women using other methods of contraception should know about ECPs and how to obtain them if needed—for example, if a condom breaks or a woman misses 3 or more combined oral contraceptive pills.
Yes. Taking ECPs is simple, and medical supervision is not needed. Studies show that young and adult women find the label and instructions easy to understand. ECPs are approved for over-the-counter sales or nonprescription use in many countries.