The U.S. Food and Drug Administration (FDA) first approved this off-label use of oral contraceptives in 1997. The first brand to receive approval, Preven™, contained both estrogen and progestin hormones. While Preven™ is no longer avialable as a brand product, other combined estrogen/progestin oral contraceptives can be prescribed by physicians for this purpose.1 The second brand approved by the FDA is Plan B™ - a progestin-only product packaged specifically for this use. There is general consensus in the medical community that these pills may operate in one of three ways:2
- To delay or prevent ovulation (the release of the woman’s egg)
- To prevent sperm from reaching the egg, preventing fertilization and acting as a contraceptive
- To alter the lining of the uterus (endometrium), preventing implantation of an early embryo after fertilization
This last point is one of major debate and one that pivots on the definition of pregnancy. Traditionally, fertilization — the joining of sperm and egg to form a zygote — is recognized as the beginning of pregnancy. Biologically, fertilization marks the creation of a genetically complete human being that only needs time, nourishment, and a place to grow.3 However, groups like the American College of Obstetricians and Gynecologists define pregnancy as “beginning with the successful implantation of a fertilized egg.”4
Based on the fertilization definition of pregnancy, "emergency contraception" may cause an early abortion. This is information women have a right to know before taking the pills.
For more information on the possible abortifacient effect of EC, see: C. Kahlenborn, et al., “Postfertilization Effect of Hormonal Emergency Contraception,” The Annals of Pharmacotherapy, March 2002.
Carrie Gordon Earll is the Senior Policy Analyst for Bioethics at Focus on the Family and a fellow with the Center for Bioethics and Human Dignity.
