Hormonal birth-control injections may double a woman's risk of contracting HIV and passing it on to her partner, according to a new study. The research comes at a time when many governments are looking to scale up their family-planning programmes in a bid to reduce maternal mortality.

Published in the 4 October 2011 online edition of The Lancet's Infectious Diseases journal, the study followed about 3,800 heterosexual couples in seven African countries over about two years. Researchers found that women who relied on hormonal shots to prevent pregnancy doubled their HIV risk. In women who were HIV-positive, using "the shot" doubled the chances that they transmitted HIV to their partners.

"This study should not result in women stopping contraception - it's too important from the individual and pubic health perspective," author Jared Baeten told IRIN/PlusNews. "It should promote a conversation about how we keep women safe while reducing unplanned pregnancy and the complications from that."