The findings, just published in the journal Contraception, may lead to new options of birth control for women with HIV. Further research should be done to confirm that clinical outcomes are consistent with conclusions that have been based on pharmacokinetic analysis, scientists said.
Worldwide, the leading cause of death among women ages 18-45 is HIV/AIDS, and prevention of mother-to-child transmission of HIV by reducing unintended pregnancy is a United Nations millennium goal for 2010-15. This research, and broad access to oral contraception, could help reach that goal.
The research was done by scientists from the Oregon State University/Oregon Health & Science University College of Pharmacy, the Albert Einstein College of Medicine and the University of Southern California.
Although millions of women around the world routinely use oral contraception, it has been largely avoided by those with HIV infections because some of the drugs commonly used to control HIV are believed to reduce the effectiveness of birth control pills.
Because of that, both the World Health Organization and Centers for Disease Control have suggested that oral contraceptives should not be used by HIV-positive women if other methods of birth control are available – such as barrier devices, IUDs or other approaches.
The new study, however, raises doubts about such a broad guideline against oral contraception. It found that while some types of oral contraceptives may be subject to this concern, others that are highly efficacious should be even more effective when particular HIV drugs are used.
“Oral contraception is used by millions of women and is among the most popular forms of birth control,” said Ganesh Cherala, an OSU assistant professor of pharmacy practice, a corresponding author on the study. Cherala is an expert in pharmacokinetics, or how drugs behave, interact and are transformed in the body.
“It’s important for women to have access to – and the ability to choose from – as wide a range of birth control options as possible,” Cherala said. “We believe this research shows the WHO guidelines are too generic and unnecessarily cautious. There clearly appear to be oral contraceptives that should be safe and effective in women being treated with HIV medications.”
In general, there are two types of oral contraceptives: “combination” drugs that include both estrogen and progestin, and drugs that are based solely on progestin for their efficacy. The concerns raised about reduced efficacy were based primarily on studies of the combination oral contraceptives, and may be valid for that group of drugs, Cherala said.
However, the new study found that progestin-only contraceptives based on at least one progestin, norethindrone, should actually have a slightly higher level of birth control efficacy, not a reduced one, when a women is taking one of the primary therapies for HIV, called a ritonavir-boosted atazanavir antiretroviral therapy.
Other progestin-only birth control drugs may also have the same properties as the ones based on norethindrone, but that has not yet been conclusively demonstrated, Cherala said.
The research was done with both treatment and control groups of women who were HIV-positive, ages 18-44, with no other recent use of hormonal contraception.
“These findings are interesting and exciting,” Cherala said. “They should ultimately give women more options to consider for birth control.”
Historically, some of the progestin-only oral contraceptives had unwanted side effects more than the combination contraceptives, Cherala said. However, those differences are now very small as improved forms of progestin-only contraceptives have come to market.
This research was supported by the National Institutes of Health.
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