Women have many choices when it comes to preventing pregnancy. Now, a new study suggests those who use an intrauterine device (IUD), versus a hormonal contraceptive, are less likely to become pregnant.

An IUD is a plastic and copper device that sits inside the womb, blocking sperm from crossing over to the fertilized egg. IUDs are considered long-term birth control because they last for five to 10 years and have no hormonal effects. There are also IUDs that contain hormones rather than copper, but these were not evaluated in this study.

Researchers reviewed data from two studies comparing IUDs and hormonal contraceptives. The studies included over 900 women from Brazil, Guatemala, Egypt, Vietnam and Zambia. In both studies, women were assigned either an IUD or hormonal contraceptive. Hormonal contraceptives were given only by injection in the first study, but women were allowed to switch between pills and injections in the second.

They found women who received the IUD were less likely to get pregnant. Researchers also found a possible link between using IUDs and slowing the progression of HIV. They stressed the need for further analysis.

“This information will be useful for counseling women regarding their choice of contraception,” Justus Hofmeyr, lead researcher from the University of Witwatersrand and Eastern Cape Department of Health in South Africa, was quoted as saying. “The importance of choice is suggested by the fact that fewer women stopped taking hormonal contraceptives when they were allowed to switch between different types.”

SOURCE: Cochrane Database of Systematic Reviews, 2010