Challenges in assessing associations between hormonal contraceptive use and the risks of HIV-1 acquisition and transmission

Effects of intrauterine contraception on the vaginal microbiota

OBJECTIVES

There have been conflicting reports of altered vaginal microbiota and infection susceptibility associated with contraception use. The objectives of this study were to determine if intrauterine contraception altered the vaginal microbiota and to compare the effects of a copper intrauterine device (Cu-IUD) and a levonorgestrel intrauterine system (LNG-IUS) on the vaginal microbiota.

STUDY DESIGN

DNA was isolated from the vaginal swab samples of 76 women using Cu-IUD (n=36) or LNG-IUS (n=40) collected prior to insertion of intrauterine contraception (baseline) and at 6 months. A third swab from approximately 12 months following insertion was available for 69 (Cu-IUD, n=33; LNG-IUS, n=36) of these women. The V4 region of the bacterial 16S rRNA-encoding gene was amplified from the vaginal swab DNA and sequenced. The 16S rRNA gene sequences were processed and analyzed using the software package mothur to compare the structure and dynamics of the vaginal bacterial communities.

RESULTS

The vaginal microbiota from individuals in this study clustered into 3 major vaginal bacterial community types: one dominated by Lactobacillus iners, one dominated by Lactobacillus crispatus and one community type that was not dominated by a single Lactobacillus species. Changes in the vaginal bacterial community composition were not associated with the use of Cu-IUD or LNG-IUS. Additionally, we did not observe a clear difference in vaginal microbiota stability with Cu-IUD versus LNG-IUS use.

CONCLUSIONS

Although the vaginal microbiota can be highly dynamic, alterations in the community associated with the use of intrauterine contraception (Cu-IUD or LNG-IUS) were not detected over 12 months.

IMPLICATIONS

We found no evidence that intrauterine contraception (Cu-IUD or LNG-IUS) altered the vaginal microbiota composition. Therefore, the use of intrauterine contraception is unlikely to shift the composition of the vaginal microbiota such that infection susceptibility is altered.

Hormonal contraceptive methods and risk of HIV acquisition in women: a systematic review of epidemiological evidence

Whether use of various types of hormonal contraception (HC) affect risk of HIV acquisition is a critical question for women's health. For this systematic review, we identified 22 studies published by January 15, 2014 which met inclusion criteria; we classified thirteen studies as having severe methodological limitations, and nine studies as "informative but with important limitations". Overall, data do not support an association between use of oral contraceptives and increased risk of HIV acquisition. Uncertainty persists regarding whether an association exists between depot-medroxyprogesterone acetate (DMPA) use and risk of HIV acquisition. Most studies suggested no significantly increased HIV risk with norethisterone enanthate (NET-EN) use, but when assessed in the same study, point estimates for NET-EN tended to be larger than for DMPA, though 95% confidence intervals overlapped substantially. No data have suggested significantly increased risk of HIV acquisition with use of implants, though data were limited. No data are available on the relationship between use of contraceptive patches, rings, or hormonal intrauterine devices and risk of HIV acquisition. Women choosing progestin-only injectable contraceptives such as DMPA or NET-EN should be informed of the current uncertainty regarding whether use of these methods increases risk of HIV acquisition, and like all women at risk of HIV, should be empowered to access and use condoms and other HIV preventative measures. Programs, practitioners, and women urgently need guidance on how to maximize health with respect to avoiding both unintended pregnancy and HIV given inconclusive or limited data for certain HC methods.

Hormonal contraception for women exposed to HIV infection

BACKGROUND

Concern about a possible association of hormonal contraception with HIV acquisition has been raised by three types of evidence. Firstly, high-dose progestogen treatment greatly increases HIV acquisition in female non-human primates. Secondly, biological plausibility for a link between hormonal contraception anf HIV acquisition is provided by evidence of a hypo-oestrogenic state induced by progestogen contraception with vaginal mucosal thinning, and evidence of effects on the humoral and cellular immune systems. Thirdly, some but not other large observational studies have found an increase in HIV acquisition among women using hormonal contraception.

OBJECTIVES

To determine, from the best available evidence, the effect of hormonal contraception on HIV acquisition.

SEARCH METHODS

We used the Cochrane Fertility Regulation Group trials search strategy.

SELECTION CRITERIA

Published, unpublished and ongoing trials with random allocation, comparing hormonal with non-hormonal methods, other hormonal methods or no contraception in women at risk of HIV acquisition.

DATA COLLECTION AND ANALYSIS

Data will be extracted from eligible trials onto a data extraction sheet and analysed using routine Cochrane Collaboration methodology,

MAIN RESULTS

One ongoing randomised trial was identified, with no data available to date.

AUTHORS' CONCLUSIONS

There is currently no robust evidence from randomized trials on the possible effect of hormonal contraception on HIV acquisition. High quality trials in this area are needed to inform counselling of individual woman and public health policy.