New study finds that subdermal implants remain a viable contraceptive option for HIV-positive women using efavirenz-based anti-retroviral therapy

A new study, published today in The Lancet HIV by researchers at the Kenya Medical Research Institute (KEMRI) and the University of California, San Francisco (UCSF), show that subdermal implants should remain a viable contraceptive option for HIV-positive women using anti-retroviral therapy (ART), including efavirenz-based ART.

Using data collected during clinical visits for HIV care at the Family AIDS Care & Education Services (FACES)-supported Ministry of Health facilities in Migori, Homabay and Kisumu counties in Kenya, the researchers followed nearly 25,000 women, between ages of 15 and 45 years, from January 2011 to December 2013. They noted the types of contraceptive methods and ART regimens the women reported using. They also tracked when these women became pregnant.

The study found that HIV-positive women who used subdermal implants and efavirenz-based ART had three times higher rates of pregnancy than women who used implants and nevirapine-based ART (3.3 pregnancies per 100 person-years vs. 1.1 pregnancies per 100 person-years, respectively). However, women who used any other method of contraception, such as depot-medroxyprogesteroneacetate—more commonly known as “Depo”—or oral contraceptive pills, than implants had 1.6-2.8 times higher rates of pregnancy while receiving efavirenz-based ART. The only exception were women who used intrauterine contraceptive devices or had hysterectomies or tubal ligations. “In other words, despite having slightly higher rates of pregnancy while using implants and efavirenz-based ART, these women were still likely to have one of the lowest pregnancy rates due to the implant’s overall effectiveness,” reports the paper’s lead author, Dr. Rena C. Patel, assistant professor at the UCSF Division of Infectious Diseases.

In general, implants are the most effective form of reversible contraception and fail less than 1% of the time. Implants are routinely placed subdermally by nurses and clinical officers in sub-Saharan Africa, and protect against pregnancy for up to 3 or 5 years depending on the type of implant used. They do not require any maintenance or return to health facilities, so an increasing number of women are choosing this convenient method of family planning.

This is the first study to comprehensively examine this important topic in the field of HIV and reproductive health. Due to some data from pharmacokinetic studies, which showed that the implant’s hormone concentrations in blood were reduced when used with efavirenz-based ART, some ministries of health in sub-Saharan Africa have recommended against the use of implants for women receiving efavirenz-based ART. Dr. Elizabeth A. Bukusi, deputy director of research and training at KEMRI and co-author on the paper says, “Efavirenz-based ART is the leading combination regimen recommended by the World Health Organization for resource-limited settings, and recommending women not use implants while on efavirenz-based ART is problematic, as alternative long-acting but reversible contraception, such as intrauterine contraceptive devices, are not readily available in Kenya.”

“This study demonstrates that while women on efavirenz-based ART using the implant have a slightly increased risk of pregnancy (on average 2 additional women out of a 100 women followed for a year may become pregnant), but that their risk of pregnancy remained extremely low and was lower than the risk of pregnancy using other reversible contraceptive methods. Counseling women who are HIV-positive about family planning options should include this information to help the patient make an informed choice,” says the paper’s senior author, Dr. Craig R. Cohen, UCSF professor in the Bixby Center for Global Reproductive Health and co-director of FACES.

While the study has some limitations, it sheds extensive light on this controversy. Future studies are needed to determine if there are ways to optimize the implant, such as shortening the duration of its use, or if implants when used in combination with other ART regimens improve protection against pregnancy. “What this problem really boils down to is providing greater access to newer ART options, which are less likely to interact with hormonal contraception, in resource-limited settings so women can continue to have the choice of using implants,” says Dr. Patel.

Supplemental Information

Web appendix 9.28.2015

EFV and implant manuscript revision 9.4.2015

Pregnancy rates with implants and efavirenz The Lancet HIV Oct 2015

For more information, contact Dr. Bukusi at EBukusi@kemri.org or Dr. Patel at rcpatel@uw.edu

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