March 11, 2014 — Two businesses' legal challenge to the federal contraceptive rules spotlights an ongoing debate about whether certain forms of emergency contraception only work by preventing fertilization or also have the ability to block a fertilized egg from implanting, Reuters reports.
Under the federal contraceptive coverage rules, most private employers are required to provide coverage of "contraceptive methods," but not of abortifacients, Reuters reports.
In the Supreme Court cases, the owners of Hobby Lobby and Conestoga Wood Specialties object on religious grounds to offering insurance coverage of emergency contraceptives that they believe prevent a fertilized egg from implanting in the uterine lining. The owners, along with many antiabortion-rights groups, contend that preventing a fertilized egg from implanting is the equivalent of an abortion. The plaintiffs do not object to contraceptives that work by preventing fertilization, according to Reuters.
Specifically, Hobby Lobby and Conestoga's owners object to three forms of EC: copper intrauterine devices; Teva Pharmaceutical's Plan B and its generic counterparts, which are available over-the-counter; and Watson Pharma's prescription-only ella.
According to Reuters, "the Supreme Court will not be ruling on the science, and has never defined pregnancy." However, many groups have filed amicus briefs in the case offering their interpretation of how EC works.
The debate also involves a dispute over when a pregnancy begins, Reuters reports. A fertilized egg cannot result in a pregnancy until it implants in the lining of the uterus. An estimated 50% to 80% of fertilized eggs fail to implant.
Most federal agencies and the American College of Obstetricians and Gynecologists define pregnancy as beginning at implantation. However, many abortion-rights opponents believe that life begins at fertilization.
Research on EC
Research continues to emerge in the underlying debate about how certain EC methods work.
According to Reuters, a copper IUD is most likely to prevent pregnancy if implanted long before ovulation, which suggests that its primary mechanism of action is disabling the sperm or egg and thereby preventing fertilization. However, Kristina Gemzell-Danielsson of Sweden's Karolinska Institute, who has reviewed over 100 studies on EC, said that if fertilization has already occurred, a copper IUD still can prevent implantation.
Most medical experts are in agreement that the latest research shows Plan B prevents pregnancy by preventing fertilization, not by blocking implantation. Although FDA as recently as 2009 had a document on its website that said the drug "may prevent a fertilized egg from attaching to the womb," the International Federation of Gynecology & Obstetrics in a 2012 analysis concluded that the drug's active compound, levonorgestrel, primarily acts by preventing or delaying ovulation.
European drug regulators in 2013 have since changed the labeling for the drug to state that it "cannot stop a fertilized egg from attaching to the womb," but it is unclear if FDA will similarly clarify its labeling. FDA spokesperson Erica Jefferson said that while the "agency is aware of emerging data that suggests that (Plan B's compound) does not inhibit or prevent implantation of the fertilized egg and acts only by blocking or delaying ovulation," it "has not had the opportunity to formally evaluate this recent data."
Ella, which is newer, has not been studied as extensively. In approving the drug in 2010, FDA said that while it primarily works "by stopping or delaying the release of an egg," it might "also work by preventing attachment." Similarly, the drug's manufacturer has said it "is possible" that ella might prevent implantation.
According to Reuters, most researchers who study contraception do not believe that ella prevents implantation. Gemzell-Danielsson said that studies show that ella, like Plan B, has no effect on the uterine lining (Begley, Reuters, 3/11).