Emergency Contraception 101
We walk you through the basics of emergency contraception so that you can make the best decision.Get Educated >
Expert Q & A
Our expert team of doctors and pharmacists answer questions about emergency contraception, and what to expect when taking it.Click Here for Answers >
Does Emergency Contraception Cause an Abortion?
Will emergency contraception cause an abortion? Do different types of emergency contraception work differently?
Progestin-only emergency contraceptive pills (ECPs, such as Plan B One-Step™ and Next Choice®) cannot cause an abortion, at least given the standard medical definition for the start of pregnancy. These pills work primarily by stopping or delaying ovulation, or preventing fertilization of the egg if ovulation has already occurred.
At times, they may also alter the lining of the uterus, making it less receptive to a fertilized egg and interfering with implantation. In addition, they may thicken the cervical mucus, which can prevent sperm from traveling through the uterus and affect their survival.
Emergency contraceptive pills will have no effect on an established, implanted pregnancy. There is one exception, which is ulipristal (ella®), a prescription-only emergency contraception. Although the available data is vague, it is likely that ulipristal might be able to disrupt an established pregnancy, based on the way it works and on its similarities to mifepristone (also known as RU-486 or "the abortion pill").
In medicine, the standard accepted definition for the start of pregnancy is when the fertilized egg implants into the uterus (implantation). However, many women feel differently and may believe that a pregnancy begins once the egg is fertilized. For these women, emergency contraceptive pills may present an ethical dilemma.