The pregnancy protection index: A framework for the systematic study of pregnancy protection

Abstract

In this article the Pregnancy Protection Index (PPI), a framework for assessing a woman's likelihood of pregnancy based on key aspects of her sexual and contraceptive behaviors, is derived in a step‐by‐step presentation. The PPI is proposed as a tool for doing two things: first, combining key factors of a subject's sexual and contraceptive practices into one summarizing measure and, second, allowing subjects to be compared along a continuous scale of pregnancy protection. More specifically, this measure indicates how protected an individual is from pregnancy based on (a) how frequently a contraceptive method is used, (b) the type(s) of contraceptive method(s) used and its (their) effectiveness, and (c) how frequently the subject has intercourse. Although it still needs empirical testing on large samples to determine its reliability and validity, the PPI has the potential for greatly assisting physicians, clinicians, and researchers alike. Instead of assessing a client's risk of pregnancy based on one factor alone, it is proposed that the PPI will help professionals combine several key factors into a comprehensive and more predictive model.