A new study from Africa reveals that using a hormone shot given every three months - the most popular contraceptive for women in eastern and southern Africa, may make it easier for HIV to spread between heterosexual sex partners.
The study shows that women who used hormonal contraception had double the risk of acquiring HIV or transmitting it to their male partners as those who did not use hormonal contraception. While hormonal conception includes both oral contraception and injectable forms of birth control, the findings were most pronounced for women using injectables, like Depo-Provera, the study said.
Study researcher Jared Baeten, of the University of Washington said, “These findings have important implications for family planning and HIV-1 prevention programs, especially in settings with high HIV-1 prevalence.” HIV-1 is the prevalent subtype of HIV. Study researcher Renee Heffron, also of the University of Washington added, “Recommendations regarding contraceptive use, particularly emphasizing the importance of dual protection with condoms and the use of non-hormonal and low-dose hormonal methods for women with or at risk for HIV-1, are urgently needed.”
Figures reveal that more than 140 million women worldwide use hormonal contraception, such as daily oral pills and long-acting injectables. About 12 million women between the ages of 15 and 49 in sub-Saharan Africa, roughly 6 percent of all women in that age group, use them. In the United States, it is 1.2 million, or 3 percent of women using contraception. While the study involved only African women, scientists said biological effects would probably be the same for all women. But they emphasized that concern was greatest in Africa because the risk of HIV transmission from heterosexual sex was so much higher there than elsewhere.
For this study the researchers included 3,790 heterosexual couples in which one partner was HIV positive and the other was not. The couples were from seven African countries (Botswana, Kenya, Rwanda, South Africa, Tanzania, Uganda and Zimbabwe).
Women using hormonal contraceptives were twice as likely to become infected with HIV. The risk was increased among those using injectable and oral contraceptives, although for the increase seen in those using oral contraceptives was smaller and may have been due to chance. Additionally, women who were HIV-positive at the beginning of the study and using injectable contraception were twice as likely to transmit the virus to their male partner as women who did not use hormonal contraception.
The results held even after researchers took into account factors that could affect the HIV transmission rate, such as the whether the woman was pregnant, and whether condoms were used. The researchers also found that oral contraceptives appeared to increase risk of HIV infection and transmission, but the number of pill users in the study was too small to be considered statistically significant, the authors said.
Researchers speculate that it is possible hormonal contraception causes biological changes, such as changes to the cells that line the vagina or cervix, that influence susceptibility to HIV.
“Active promotion of [injectable contraceptives] in areas with high HIV incidence could be contributing to the HIV epidemic in sub-Saharan Africa, which would be tragic,” Charles Morrison from Clinical Sciences, Durham, North Carolina, said in an accompanying editorial. “Conversely, limiting one of the most highly used effective methods of contraception in sub-Saharan Africa would probably contribute to increased maternal mortality and morbidity and more low birth weight babies and orphans — an equally tragic result,” Morrison said.
Morrison however added that the study was not originally designed to measure the effect of hormonal contraception on HIV risk, and that the number of women using these contraceptives was small. In addition, it was common for women in the study to switch their contraception method, from hormonal to non-hormonal contraception, such as intrauterine devices. It's time to find a definitive answer to the question of whether hormonal contraception increases HIV acquisition risk, Morrison said.
“The best contraception today is injectable hormonal contraception because you don’t need a doctor, it’s long-lasting, it enables women to control timing and spacing of birth without a lot of fuss and travel,” said Isobel Coleman, director of the women and foreign policy program at the Council on Foreign Relations. “If it is now proven that these contraceptions are helping spread the AIDS epidemic, we have a major health crisis on our hands.”
“We are going to be re-evaluating W.H.O.’s clinical recommendations on contraceptive use,” said Mary Lyn Gaffield, an epidemiologist in the World Health Organization’s department of reproductive health and research. Before the meeting, scientists will review research concerning hormonal contraceptives and women’s risk of acquiring HIV, transmitting it to men, and the possibility (not examined in the new study) that hormonal contraceptives accelerate HIV’s severity in infected women. “We want to make sure that we warn when there is a real need to warn, but at the same time we don’t want to come up with a hasty judgment that would have far-reaching severe consequences for the sexual and reproductive health of women,” she said. “This is a very difficult dilemma.”
The research was presented at an international AIDS conference this summer, but has now gained traction, scientists said, with publication in a major peer-reviewed journal.
The manufacturer of the branded version of the injectable, Depo-Provera, is Pfizer, which declined to comment on the study, saying officials had not yet read it. The study’s authors said the injectables used by the African women were probably generic versions.
Dr. Ludo Lavreys, an epidemiologist who led one of the first studies to link injectable contraceptives to increased HIV risk, said intrauterine devices, implants and other methods should be explored and expanded. “Before you stop” recommending injectables, he said, “you have to offer them something else.”
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