How abortion drugs differ from “Plan B” and other emergency contraceptives
Recent Supreme Court decision overturned Roe v. calfthe nearly 50-year-old precedent guaranteeing a constitutional right to abortion has people struggling to access drugs that can terminate or prevent pregnancy.
But there is already confusion about the difference between medical abortion drugs, which are prescribed to terminate a pregnancy, and emergency contraception (including Plan B), which are taken shortly after sex and impede Pregnancy.
Medical abortion in the US usually consists of a combination of two drugs, both taken orally after consultation with a medical provider. Approved by the Food and Drug Administration, this protocol includes the drugs mifepristone and misoprostol. They work together by causing something like heavy menstruation.
Mifepristone (Mifeprex), also known as RU-486, is taken within 10 weeks of a pregnant person’s last period. It blocks receptors for the hormone progesterone, causing the embryo to detach from the uterine wall and breaking down the lining of the uterus, terminating the pregnancy. Misoprostol (Cytotec), a synthetic form of a prostaglandin, a group of compounds with hormone-like effects, is taken within a day or two of mifepristone. It causes the uterus to contract and the cervix to soften, which allows the uterus to empty. Misoprostol can be taken alone to induce termination of pregnancy, but is more effective when taken with mifepristone.
In contrast, emergency contraception — sometimes called the morning-after pill — can be taken for up to three to five days after unprotected sex or birth control failure. This type of drug works mainly by preventing or delaying ovulation, or the release of an egg from an ovary. If ovulation has already occurred, it has been hypothesized that the morning-after pill could prevent fertilization or implantation of the egg in the uterus, although some studies suggest that it does not affect these processes. Importantly, emergency contraception cannot terminate a pregnancy, which the medical community defines as a fertilized egg that has implanted in the uterus.
“The key difference between emergency contraception and medical abortion is that emergency contraception prevents pregnancy from occurring, while medical abortion terminates a pregnancy,” says Jen Villavicencio, director of equity transformation at the American College of Obstetricians and Gynecologists.
There are several types of morning-after pill: Plan B, perhaps the most well-known, consists of the synthetic hormone levonorgestrel and works by preventing or delaying ovulation. It is available without a prescription and can be taken within 72 hours of having sex (the sooner Plan B is taken, the more effective it is). However, it may not be suitable for people heavier than about 155 to 165 pounds. “Plan B is incapable of inducing an abortion,” a spokesman for Foundation Consumer Healthcare, the company that owns Plan B, wrote in an email Scientific American.
Another emergency contraceptive called Ella is effective in people weighing up to 195 pounds. It contains a drug called ulipristal acetate and works like Plan B by preventing or delaying ovulation. Ella requires a prescription and can be taken within five days of unprotected sex, but the earlier it is taken, the better its effects.
Despite the fact that the morning-after pill does not terminate an existing pregnancy, clinics in some states may misinterpret abortion restrictions as bans on emergency contraception as well. The Saint Luke health system in Kansas City, Missouri, initially stopped providing Plan B at its locations in the state, which has banned most abortions, including those for rape or incest. “To ensure we comply with all state and federal laws — and until the law in this area is better defined — Saint Luke’s will not be offering emergency contraception at our Missouri locations,” Saint Luke’s health care system spokeswoman Laurel Gifford said in a statement June 28 statement reported by the Kansas City Star and other outlets. But the next day, the health system said it would resume emergency contraception.
Emergency contraception “should never be subject to laws that ban abortion,” says Villavicencio. “Any impact of abortion bans on emergency contraception is a misapplication of the law and a misunderstanding of medical science.”
Contraception — including emergency contraception — remains legal in Missouri and across the country. But situations like that in Kansas City suggest that abortion-restricting laws could have a chilling effect on access to contraceptives like Plan B. And it’s not far-fetched to think that the Supreme Court could ultimately roll back protections for contraception in general: in its affirmative opinion in the court’s recent decision in Dobbs v. Jackson Women’s Health Organizationwho fell over Roe v. calfJudge Clarence Thomas wrote that the court should consider other cases, including Griswold vs. Connecticut– a 1965 decision affirming the freedom of married couples to buy and use contraceptives.
Right now, it’s important for patients and policymakers to understand the difference between medicated abortion drugs, which are now illegal to prescribe in some states, and emergency contraception, which are legal across the country.
“Denying people emergency contraception will only result in more people having to face the realities of unwanted pregnancy without legal abortion treatment as a solution,” Villavicencio says.