The most effective birth control methods for women with HIV are implants and injectable hormonal contraceptives, according to an analysis of data on more than 5,000 HIV-positive women participating in three major studies.

The new analysis “was one of the largest that was able to look at how women use birth control in the real world and to follow women through to pregnancy,” says the study’s lead author, Maria Pyra, MPH, a research assistant at the University of Washington.

Pyra and her colleagues estimated that implants cut pregnancy risk among those who did and did not take antiretrovirals (ARVs) for HIV by a respective 94 and 95 percent. Injectable contraceptives reduced pregnancy risk among those taking and not taking ARVs by a respective 82 and 80 percent. Oral contraceptives reduced pregnancy rates among both those taking and not taking ARVs by around 60 percent.