Intrauterine Devices Result in Fewer Unwanted Pregnancies

A new study claims that intrauterine devices (IUDs) and contraceptive implants are far more effective in preventing unwanted pregnancies than pill, patch, or ring (PPR) methods.

Researchers at Washington University (St. Louis, MO, USA; wustl.edu) conducted a prospective cohort study involving 7,486 445 sexually active women, including teens as young as 14, from August 2007 to September 2011. The researchers compared the rate of failure of long-acting reversible contraception--intrauterine devices (IUDs) and subdermal hormonal implants--with other commonly prescribed contraceptive methods, including oral contraceptive pills, transdermal patches, contraceptive vaginal rings, and depot medroxyprogesterone acetate (DMPA) injection; the reversible contraception was provided at no cost.

In all, the researchers identified 334 unintended pregnancies. Contraceptive failure rate among participants using PPR was 4.55 per 100 participant-years, as compared with 0.27 among participants using long-acting reversible contraception. Among participants who used PPR who were less than 21 years of age, the risk of unintended pregnancy was almost twice as high as among the older participants. Rates of unintended pregnancy were similarly low among participants using DMPA injection and those using an IUD or implant, regardless of age. The study was published in the May 24, 2012, issue of the New England Journal of Medicine (NEJM).

“Half of all pregnancies in the United States are unintended, and half of those result from contraceptive failure,” concluded lead author Jeffrey Piepert, MD, PhD, and colleagues. “If more women used the highly effective, long-acting reversible methods, we would expect a decrease in the number of unintended pregnancies, because there would be more women continuing to use contraception.”

The researchers suggested that with few contraindications to IUDs and the subdermal implant, these products should be the smart choice for almost all sexually active women who do not want to become pregnant, especially in adolescents, for whom failure of PPR methods is especially common.

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