Informed consent and the redefining of conception: a decision ill-conceived?

The purposes of this study are to assess the use of the American College of Obstetricians and Gynecologists' (ACOG) definitions of conception (a synonym for implantation) and the beginning of pregnancy (at implantation) in the clinical practice of its members and to explore the implications of differing definitions of conception and pregnancy onset for the process of informed consent. A survey was mailed to 112 members of the Louisville Ob/Gyn Society asking what definition of conception they used in their clinical practice and when they judged pregnancy began. A second mailing was sent to nonresponding members. Using logistic regression analysis, the responses to these questions were evaluated with respect to practice type, number of years in practice, and the ACOG membership. Responses were received from 86% (96 of 112) of the members. A total of 73% (70 of 96) (95% CI 69-77%) of the members indicated that conception was a synonym for fertilization, and 24% (23 of 96) (95% CI 21-28%) indicated that conception was a synonym for implantation (P < .001). Of the members, 50% (48 of 96) indicated that pregnancy began at fertilization, and 48% (46 of 96) indicated that pregnancy began with implantation (NS). Regression analysis failed to demonstrate a significant relationship to type of practice, years in practice, or the ACOG membership for these responses. Neither ACOG definition has been consistently adopted by its members whose definitions are more consistent with lay and embryologist definitions. Potentially, the process of informed consent is jeopardized by these ambiguities. The ACOG is urged to reconsider its definitions.