Achilles SL, et al. - In view of the limited and inconsistent data evaluating the impact of contraceptives on the vaginal microbiome, researchers here tested if women initiating copper intrauterine device use would have increased bacterial vaginosis and bacterial vaginosis-associated microbes with use compared to women initiating and using hormonal contraceptive methods. Findings suggested an increase in the colonization by bacterial vaginosis (BV)-associated microbiota in association with copper intrauterine device use, resulting in increased prevalence of BV. No alteration in vaginal microbiota was evident with the use of most hormonal contraception.

Methods

• From asymptomatic, healthy women aged 18-35 in Harare, Zimbabwe who were confirmed to be free of non-study hormones by mass spectrometry, researchers collected vaginal swabs (N=1047 from 266 participants seeking contraception) for Nugent score determination of bacterial vaginosis (BV) and quantitative polymerase chain reaction analyses for assessment of specific microbiota.
• They initiated contraception with an injectable (depot medroxyprogesterone acetate (n=41), norethisterone enanthate (n=44), or medroxyprogesterone acetate and ethinyl estradiol (n=40)), implant (levonorgestrel- (n=45) or etonogestrel-implant (n=48)), or copper intrauterine device (n=48) and collected repeat vaginal swabs after 30, 90 and 180-days of continuous use.
• Across all arms, self-reported condom use was similar at baseline.
• They used quantitative polymerase chain reaction to detect Lactobacillus crispatus, Lactobacillus jensenii, Lactobacillus gasseri/johnsonii group, Lactobacillus vaginalis, Lactobacillus iners, Gardnerella vaginalis, Atopobium vaginae and Megasphaera-like bacterium phylotype I from swabs.
• To compare marginal prevalence and mean difference in quantity (expressed as gene copies/swab) prior to and during contraceptive use, they used Modified Poisson regression and mixed effects linear models.

Results

• Women initiating copper intrauterine devices showed increase in BV prevalence from 27% at baseline to 35% at 30 days, 40% at 90 days and 49% at 180 days (p=.005 compared to marginal prevalence at enrollment).
• No change in BV prevalence over 180 days was evident among women initiating hormonal methods.
• In women using copper intrauterine devices, the mean increase in Nugent score was 1.2 (95% CI 0.5-2.0, p=.001).
• Intrauterine device users did not show change in the frequency and density of beneficial lactobacilli over six months, however, there was an increase in the log concentration of Gardnerella vaginalis (4.7, 5.2, 5.8, 5.9; p=.046) and Atopobium vaginae (3.0, 3.8, 4.6, 5.1; p=.002) between baseline and 30, 90 and 180 days after initiation.
• Among other contraceptive groups, women using depot medroxyprogesterone acetate showed decreased Lactobacillus iners (mean decrease log concentration= 0.8; 95% CI: 0.3, 1.5, p=.004); no significant changes in beneficial Lactobacillus species was observed over 180 days regardless of contraceptive method used.