What influences the effectiveness of contraceptives?

Contraceptive choice was associated with a range of socioeconomic and partnership characteristics, and with pregnancy-, method- and provider-related experiences and attitudes; inconsistent pill or condom use was associated mainly with partnership, experiential and attitudinal factors. For example, not having a college education was negatively associated with pill use (odds ratio, 0.6) and positively associated with use of long-acting methods (1.8– 1.9).Women for whom avoiding pregnancy was only a little or not important had reduced odds of using the pill (0.4) and elevated odds of using other methods, such as withdrawal or periodic abstinence (4.4), and of using condoms inconsistently (2.6). Use of a method chosen mostly out of dislike of other methods was positively associated with condom use (4.0) and negatively associated with use of the pill or long-acting methods (0.4 for each). Women who were not completely satisfied with their method were more likely than others to use their method inconsistently (1.6 for pill users and 1.9 for condom users).

Greater efforts are needed to provide women and their partners with a range of method options, to facilitate selection of methods that best suit their needs and circumstances, and to identify and assist users who are dissatisfied or are having difficulties using contraceptives effectively.

The overwhelming majority of fertile, sexually active women of reproductive age in the United States who do not want to become pregnant practice contraception (89% in 2002).1 Half of all unintended pregnancies—some 1.5 million annually—occur among contraceptive users;2 of these, nine in 10 result from inconsistent or incorrect method use, and only one in 10 from method failure.*

Because contraceptive methods differ in effectiveness and because consistent and correct use is often difficult, estimated perfect-use failure rates and typical-use failure rates differ widely. For example, oral contraceptives have a perfect-use failure rate of 0.3% and a typical-use failure rate of 8%; for condoms, rates are 2% and 15%.3 Although failing to adhere to a medication’s requirements can reduce its effectiveness, roughly half of people taking medication do not take it as prescribed.4–6 It is therefore not surprising that many women and men have difficulty using contraceptives according to methods’ particular requirements.7–10

Explanation: