Why do women experience untimed pregnancies? A review of contraceptive failure rates.

Contraceptive failure contributes to a substantial proportion of unintended pregnancy, particularly in the developed world. A number of socio-demographic factors seem to impact on the risk of a woman experiencing contraceptive failure. Many of the issues exist across cultural boundaries and are complex to address. In discussing the failure rates for individual contraceptive methods, this article will highlight the advantage of improving uptake of long-acting reversible methods of contraception which have a high efficacy and are less user-dependent than many of the other available methods.