Research Article: Impact of contraceptive initiation on vaginal microbiota

Date Published: June 1, 2018

Publisher: Elsevier

Author(s): Sharon L. Achilles, Michele N. Austin, Leslie A. Meyn, Felix Mhlanga, Zvavahera M. Chirenje, Sharon L. Hillier.

http://doi.org/10.1016/j.ajog.2018.02.017

Abstract

Data evaluating the impact of contraceptives on the vaginal microbiome are limited and inconsistent.

We hypothesized that 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.

Vaginal swabs (N = 1047 from 266 participants seeking contraception) for Nugent score determination of bacterial vaginosis and quantitative polymerase chain reaction analyses for assessment of specific microbiota were collected from asymptomatic, healthy women aged 18-35 years in Harare, Zimbabwe, who were confirmed to be free of nonstudy hormones by mass spectrometry at each visit. Contraception was initiated 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 [n = 48]), or copper intrauterine device (n = 48) and repeat vaginal swabs were collected after 30, 90, and 180 days of continuous use. Self-reported condom use was similar across all arms at baseline. Quantitative polymerase chain reaction was used to detect Lactobacillus crispatus, L jensenii, L gasseri/johnsonii group, L vaginalis, L iners, Gardnerella vaginalis, Atopobium vaginae, and Megasphaera-like bacterium phylotype I from swabs. Modified Poisson regression and mixed effects linear models were used to compare marginal prevalence and mean difference in quantity (expressed as gene copies/swab) prior to and during contraceptive use.

Bacterial vaginosis prevalence increased in women initiating copper intrauterine devices from 27% at baseline, 35% at 30 days, 40% at 90 days, and 49% at 180 days (P = .005 compared to marginal prevalence at enrollment). Women initiating hormonal methods had no change in bacterial vaginosis prevalence over 180 days. The mean increase in Nugent score was 1.2 (95% confidence interval, 0.5–2.0; P = .001) in women using copper intrauterine devices. Although the frequency and density of beneficial lactobacilli did not change among intrauterine device users over 6 months, there was an increase in the log concentration of G vaginalis (4.7, 5.2, 5.8, 5.9; P = .046) and A 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 had decreased L iners (mean decrease log concentration = 0.8; 95% confidence interval, 0.3–1.5; P = .004) and there were no significant changes in beneficial Lactobacillus species over 180 days regardless of contraceptive method used.

Copper intrauterine device use may increase colonization by bacterial vaginosis–associated microbiota, resulting in increased prevalence of bacterial vaginosis. Use of most hormonal contraception does not alter vaginal microbiota.

Partial Text

Reproductive-aged women commonly use and frequently change contraceptive methods. Understanding the impact of contraceptive initiation and use on vaginal microbiota is important since perturbations often cause distressing symptoms and bacterial vaginosis (BV) has been associated with increased risk of sexually transmitted infections,1, 2, 3 including HIV.4, 5, 6 Systematic review of studies evaluating the risk of HIV acquisition and contraceptive use suggests that depot medroxyprogesterone acetate (DMPA) may increase the risk of HIV acquisition.7 The possibility that contraceptive use may alter HIV susceptibility warrants further investigation of potential mechanisms, including understanding the impact on the vaginal microbiota.8AJOG at a GlanceWhy was this study conducted?This study was conducted to evaluate the impact of contraceptive use on the vaginal microbiome of Zimbabwean women.Key findingsKey findings include that hormonal contraceptive use did not alter vaginal microbiota over 6 months, while copper intrauterine device use was associated with increased bacterial vaginosis and associated microbiota, including Gardnerella vaginalis and Atopobium vaginae.What does this add to what is known?These data from a population of African women contribute to the body of evidence from the United States suggesting women using copper intrauterine devices are more likely to have changes in the vaginal microbiome including an increase in asymptomatic and symptomatic bacterial vaginosis.

In this study, we found increased colonization by the BV-associated microbiota G vaginalis and A vaginae, as well as increased prevalence of BV during the 6-month study duration in women who opted to initiate and use copper IUD. Since women in this study who chose IUDs reported a somewhat lower frequency of vaginal intercourse relative to women who chose one of the other contraceptives, the positive association between BV and IUD cannot be explained by increased sexual activity. Use of hormonal contraceptives over 6 months did not appear to significantly shift vaginal microbial populations including beneficial Lactobacillus species or common BV-associated species.

 

Source:

http://doi.org/10.1016/j.ajog.2018.02.017

 

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