Contraceptive failure rates describe the risk of becoming pregnant among users of each contraceptive method; they are used to inform individuals’ method choice. The effectiveness of contraceptive methods varies according to many different factors, including how difficult the methods are to use consistently and correctly. These failure-rate estimates are based on the experiences of individuals who use the methods and may change over time. The estimates provided below are based on the most recent studies available.
Contraceptive failure rates are defined as the proportion of women who will become pregnant within the first 12 months after initiating method use. Typical-use failure rates express effectiveness among all women who use the method, including those who use it inconsistently and incorrectly.* Perfect-use failure rates express effectiveness among only those women who use the method both consistently and correctly.