New research suggests women who use a contraceptive jab are at greater risk of contracting HIV than those who use other forms of birth control or none at all, according to a Daily Mail report. A study found they had a 40% chance of becoming infected with HIV.
The injected contraceptive is known as depot medroxyprogesterone acetate (DMPA), commonly known as Depo-Provera or the birth control shot.
The study, involving a review of 12 studies of more than 39,500 women, found other forms of hormonal contraception, including oral contraceptive pills, do not appear to increase this risk. However, researchers stressed that although statistically significant, the figure represents only a moderate increase in relative risk.
And the risk appeared to be lower among women in the general population which saw the risk increase by 31% than for women already at high risk of acquiring HIV, such as prostitutes.
However the researchers do not explain why the link may be higher.
Worldwide about 144m women use hormonal contraception – around 41m use the injectable forms and 103m take the oral contraceptive pill.
Whether or not use of hormonal contraceptives increases women's risk of HIV acquisition has been hotly debated for more than two decades, but the research so far has been inconclusive.
However the researchers, from the University of California at Berkeley, said their findings did not warrant the injection being withdrawn.
Epidemiologist Lauren Ralph said: The moderate elevation in risk observed in our study is not enough to justify a complete withdrawal of DMPA for women in the general population.
'Banning DMPA would leave many women without immediate access to alternative, effective contraceptive options.
'This is likely to lead to more unintended pregnancies, and because childbirth remains life-threatening in many developing countries, could increase overall deaths among women.
The possible rise in HIV infections among women using the contraceptive jab was first noted in 1991. The debate over it has become "increasingly narrow and fierce", said Christopher Colvin from the University of Cape Town in South Africa and Abigail Harrison from Brown University School of Public Health in a comment on the research, reports The Guardian.
"Like many scientific controversies, views have become hardened, personal, financial, or political agendas have been suggested, and there has even been intrigue in the form of leaked copies of articles under peer review," said the commentary.
"Both sides have raised important, compelling arguments, but their partisan character can weaken the quality of the debates and restrict the view of the complex relation between evidence, policy, and practice."
The debate is currently focused on whether there should be a large randomised controlled trial. This would need to compare HIV infections of women using the birth control jab probably with another group using the pill. Some would say that in the light of current evidence that would be unethical. Others warn a trial may not be decisive. Colvin said that although trials can sometimes be the best option, they have their limitations.
"I do think that the debate over the trial, in both public and scientific circles, tends towards framing a trial as the way to ‘get the answer’ … which makes me nervous," he said.
The World Health Organisation advises that women at high risk of HIV should be told that the injectables "may or may not increase their risk of HIV acquisition". Couples should be informed and given access to other methods, including male and female condoms.
[link url="http://www.dailymail.co.uk/health/article-2902289/Women-contraceptive-jab-greater-risk-contracting-HIV.html"]Full Daily Mail report[/link]
[link url="http://www.thelancet.com/journals/laninf/article/PIIS1473-3099%2814%2971052-7/abstract"]The Lancet Infectious Diseases article summary[/link]
[link url="http://www.theguardian.com/society/2015/jan/09/contraceptive-injection-hiv-risk-birth-control-jab-lancet"]Full report in The Guardian[/link]
[link url="http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(14)71076-X/abstract"]The Lancet Infectious Diseases comment summary[/link]