Our Bodies, Our Blog

Science Says: Emergency Contraception Does Not Block Implantation of a Fertilized Egg

By Rachel Walden |

Last week, in a post about how some types of emergency contraception are less effective or ineffective in women weighing more than 165 pounds, we mentioned that the European equivalent to Plan B One-Step was getting a new label that will note the problem.

Let’s take a look at the other reason for the label change: European health officials have determined — and want to make clear — that the drug “cannot stop a fertilized egg from attaching to the womb.”

This is a big issue, as abortion opponents have long opposed EC on the grounds that it might prevent a fertilized egg from implanting in the uterus. U.S. labels of levonorgestrel-containing emergency contraceptive pills, such as Plan B, don’t directly refute the possibility.

But as The New York Times noted last year, recent science suggests that this is not the case; the pills work only by preventing ovulation and fertilization.

Last week, NYT reporter Pam Belluck noted how the FDA and other health agencies responded to the scientific studies:

References to the possibility of blocking implantation were then removed from the websites of the National Institutes of Health and the Mayo Clinic. And an F.D.A. spokeswoman, Erica Jefferson, said that “the emerging data on Plan B suggest that it does not inhibit implantation.”

On Tuesday, Ms. Jefferson reiterated that view. The drug agency has not moved to change the label, saying manufacturers must request a change. Plan B One-Step’s manufacturer, Teva Pharmaceuticals, declined to comment. It had previously said scientific evidence suggested that the pill did not disrupt implantation.

Although pregnancy is not medically considered to have begun until a fertilized egg has successfully implanted in the lining of the uterus, media coverage around this topic has often obscured this distinction and promoted a false idea that emergency contraception is the same thing as the abortion pill (RU-486) or abortion in general. Medical professionals generally assert that “emergency contraception is not effective after implantation; therefore, it is not an abortifacient.”

Effect on Lawsuits

Hobby Lobby is one for-profit corporation that filed suit to avoid complying with Obamacare coverage for contraception, claiming that forms of contraception that could interfere with the implantation of a fertilized egg are tantamount to abortion. The Supreme Court will hear the case, focusing on whether for-profit companies can be required to provide coverage that may conflict with the private religious beliefs of the business owners.

As Linda Greenhouse wrote in an op-ed about challenges to the contraception mandate under the Affordable Care Act, a coalition of medical groups, led by Physicians for Reproductive Health, filed a brief in the case, noting in part that “the weight of the scientific evidence establishes that the FDA-approved contraceptives and emergency contraceptive are not abortifacients.”

Read Greenhouse’s column for an excellent look at how the religious-based challenges represent a culture war on “modernity.” For more on the lawsuits, SCOTUSblog is a smart resource.

And we highly recommend the Emergency Contraception website for easy-to-understand fact sheets, such as this one: “Does emergency contraception cause an abortion?