Embryocidal Effects of Contemporary Contraceptives: A Review

The mechanism of action of contraceptive drugs and devices forms an essential part of informed consent for patients considering various methods of family planning. Currently the literature is confusing at best, in part due to non-uniform definitions of basic terms, as well as the misinterpretation of endpoints of current. AAPLOG members take different positions on the issue of contraception per se. The purpose of this document is to investigate and summarize the current evidence-based concerns regarding potential embryocidal mechanisms of action of modern contraceptive drugs and devices. There are three reasons for concern about embryos conceived during the use of a particular contraceptive drug or device: 1. 1) All contraceptive drugs and devices “fail” at a certain rate. As noted in a recent paper, “Unintended pregnancies occur with all contraceptive methods, including IUDs. This provides incontrovertible evidence that fertilization and implantation can occur, albeit rarely, with modern methods of contraception.”1 2. 2) Since pregnancies can and do occur during the use of all contraceptive drugs and devices, then we know by definition that fertilization, which marks the beginning of an embryonic human organism, can and does happen with all contraceptive drugs and devices since by definition, an embryo must be created for pregnancy to occur. That means embryos are created at a certain rate with all contraceptive drugs or devices. 3. 3) The contraceptive drug or device will create a certain environment for the embryos created during their use. This environment may adversely affect embryo survival up to the point of yielding a positive pregnancy test at the end of the cycle (the contraceptive efficacy end point). The remainder of this article will try to summarize what is known in the published medical literature about the environment facing an embryo who has been created during the use of various kinds of contraceptive drugs or devices.