Use of copper intrauterine device is not associated with higher bacterial vaginosis prevalence in Thai HIV-positive women

An Integrative Review of the Relationship Between Intrauterine Devices and Bacterial Vaginosis

OBJECTIVE

To examine the relationship between intrauterine devices (IUDs) and bacterial vaginosis (BV) through an integrative review of the current literature.

DATA SOURCES

CINAHL, MEDLINE, Health Source, Evidence-Based Medicine's Cochrane Central Registry of Controlled Trials, Embase, and Web of Science databases were searched.

STUDY SELECTION

Cross-sectional, case-control, cohort, quasi-experimental, and randomized controlled trials examining copper (Cu-IUD) and levonorgestrel (LNG-IUD) use in reproductive- age users with BV occurrence confirmed with Amsel's criteria or Nugent scoring were included. Articles included were published in the past 10 years.

DATA EXTRACTION

Fifteen studies met criteria, after an initial search identified 1,140 potential titles, and two reviewers assessed 62 full-text articles for inclusion.

DATA SYNTHESIS

Data were categorized into three groups: retrospective descriptive cross-sectional studies identifying point prevalence of BV among IUD users; prospective analytic studies examining BV incidence and prevalence among Cu-IUD users; and prospective analytic studies examining BV incidence and prevalence among LNG-IUD users.

CONCLUSION

Synthesis and comparison of studies were difficult because of disparate study designs, sample sizes, comparator groups, and inclusion criteria for individual studies. Synthesis of data from cross-sectional studies showed that all IUD users combined may have an increased point prevalence of BV compared with non-IUD users. These studies did not delineate LNG-IUDs from Cu-IUDs. Findings from cohort and experimental studies suggest a possible increase in BV occurrence among Cu-IUD users. Evidence is lacking to show an association between LNG-IUD use and BV.

Topical reinforcement of the cervical mucus barrier to sperm

Close to half of the world's pregnancies are still unplanned, reflecting a clear unmet need in contraception. Ideally, a contraceptive would provide the high efficacy of hormonal treatments, without systemic side effects. Here, we studied topical reinforcement of the cervical mucus by chitosan mucoadhesive polymers as a form of female contraceptive. Chitosans larger than 7 kDa effectively cross-linked human ovulatory cervical mucus to prevent sperm penetration in vitro. We then demonstrated in vivo using the ewe as a model that vaginal gels containing chitosan could stop ram sperm at the entrance of the cervical canal and prevent them from reaching the uterus, whereas the same gels without chitosan did not substantially limit sperm migration. Chitosan did not affect sperm motility in vitro or in vivo, suggesting reinforcement of the mucus physical barrier as the primary mechanism of action. The chitosan formulations did not damage or irritate the ewe vaginal epithelium, in contrast to nonoxynol-9 spermicide. The demonstration that cervical mucus can be reinforced topically to create an effective barrier to sperm may therefore form the technological basis for muco-cervical barrier contraceptives with the potential to become an alternative to hormonal contraceptives.

Elevated Risk of Bacterial Vaginosis Among Users of the Copper Intrauterine Device: A Prospective Longitudinal Cohort Study

BACKGROUND

Limited evidence suggests that the nonhormonal contraceptive copper intrauterine device (Cu-IUD) may increase bacterial vaginosis (BV) risk, possibly due to increased volume and duration of menses, a common side effect of Cu-IUD use. Although increases in bleeding typically resolve within 6-12 months following initiation, evaluations of the association between Cu-IUD and BV have not included more than 6 months of follow-up.

METHODS

This secondary analysis of a human immunodeficiency virus type 1 prevention trial included 2585 African women ages 18-45 followed for up to 33 months. Women reported contraceptive use each month. BV was evaluated by Nugent score in 6-monthly intervals and, if clinically indicated, by Amsel criteria. Andersen-Gill proportional hazards models were used to (1) evaluate BV risk among Cu-IUD users relative to women using no/another nonhormonal contraceptive and (2) test changes in BV frequency before, while using, and following Cu-IUD discontinuation.

RESULTS

BV frequency was highest among Cu-IUD users at 153.6 episodes per 100 person-years (95% confidence interval [CI]: 145.2, 162.4). In adjusted models, Cu-IUD users experienced 1.28-fold (95% CI: 1.12, 1.46) higher BV risk relative to women using no/another nonhormonal contraception. Compared to the 6 months prior to initiation, BV risk was 1.52-fold (95% CI: 1.16, 2.00) higher in the first 6 months of Cu-IUD use and remained elevated over 18 months of use (P < .05). Among women who discontinued Cu-IUD, BV frequency was similar to pre-initiation rates within 1 year.

CONCLUSIONS

Cu-IUD users experienced elevated BV risk that persisted throughout use. Women and their providers may wish to consider BV risk when discussing contraceptive options.

The effect of different contraceptive methods on the vaginal microbiome

Introduction: Following a historical overview, the effect of different contraceptive methods on vaginal microbiome has been reviewed and summarized.Areas covered: Effects of combined hormonal contraceptives (oral or vaginal) and of progestin only (injectable and implantable), intrauterine devices/systems (copper- or levonorgestrel-releasing), on vaginal microbiome. In addition, mention is made of vaginal rings releasing antiviral drugs and lactic acid.Expert opinion: The vaginal microbiota (VM) is unique in that it is normally dominated by Lactobacillus species providing a degree of protection against infections; this however may vary, depending on the species and strains of Lactobacillus. Bacterial Vaginosis represents the most common dysbiosis of the VM and its prevalence can be influenced by use of contraception. Available evidence indicates that, under the influence of oral or systemically administered female sex hormones, there is apromotion of vaginal eubiosis, with aprevalence of ahealthy VM in which Lactobacilli predominate.

Obesity is associated with lower bacterial vaginosis prevalence in menopausal but not pre-menopausal women in a retrospective analysis of the Women's Interagency HIV Study

The vaginal microbiota is known to impact women's health, but the biological factors that influence the composition of the microbiota are not fully understood. We previously observed that levels of glycogen in the lumen of the vagina were higher in women that had a high body mass index (BMI). Vaginal glycogen is thought to impact the composition of the vaginal microbiota. We therefore sought to determine if BMI was associated having or not having bacterial vaginosis (BV), as determined by the Amsel criteria. We also hypothesized that increased blood glucose levels could lead to the previously-observed higher vaginal glycogen levels and therefore investigated if hemoglobin A1c levels were associated with BV. We analyzed data from the Women's Interagency HIV Study using multiple multivariable (GEE) logistic regression models to assess the relationship between BMI, BV and blood glucose. Women with a BMI >30 kg/m2 (obese) had a lower rate (multivariable adjusted OR 0.87 (0.79-0.97), p = 0.009) of BV compared to the reference group (BMI 18.5-24.9 kg/m2). There was a significantly lower rate of BV in post-menopausal obese women compared to the post-menopausal reference group, but not in pre-menopausal women. HIV- post-menopausal obese women had a significantly lower rate of BV, but this was not seen in HIV+ post-menopausal obese women. Pre-menopausal women with a higher hemoglobin A1c (≥6.5%) had a significantly lower rate (multivariable adjusted OR 0.66 (0.49-0.91), p = 0.010) of BV compared to pre-menopausal women with normal hemoglobin A1c levels (<5.7%), but there was no difference in post-menopausal women. This study shows an inverse association of BMI with BV in post-menopausal women and hemoglobin A1c with BV in pre-menopausal women. Further studies are needed to confirm these relationships in other cohorts across different reproductive stages and to identify underlying mechanisms for these observed associations.