Self-reported bacterial vaginosis and risk of ultrasound-diagnosed incident uterine fibroid cases in a prospective cohort study of young African American women

Uterine fibroids and longitudinal profiles of the vaginal microbiota in a cohort presenting for transvaginal ultrasound

Bacterial vaginosis, characterized in part by low levels of vaginal Lactobacillus species, has been associated with pro-inflammatory cytokines which could fuel uterine fibroid development. However, prior work on the associations between uterine fibroids and vaginal bacteria is sparse. Most studies have focused on assessment of individual taxa in a single sample. To address research gaps, we sought to compare short, longitudinal profiles of the vaginal microbiota in uterine fibroid cases versus controls with assessment for hormonal contraceptives (HCs), a possible confounder associated with both protection from fibroid development and increases in Lactobacillus-dominated vaginal microbiota. This is a secondary analysis of 83 reproductive-age cisgender women who presented for transvaginal ultrasound (TVUS) and self-collected mid-vaginal swabs daily for 1-2 weeks before TVUS (Range: 5-16 days, n = 697 samples). Sonography reports detailed uterine fibroid characteristics (N = 21 cases). Vaginal microbiota was assessed by 16S rRNA gene amplicon sequencing and longitudinal microbiota profiles were categorized by hierarchical clustering. We compared longitudinal profiles of the vaginal microbiota among fibroid cases and controls with exact logistic regression. Common indications for TVUS included pelvic mass (34%) and pelvic pain (39%). Fibroid cases tended to be older and report Black race. Cases less often reported HCs versus controls (32% vs. 58%). A larger proportion of cases had low-Lactobacillus longitudinal profiles (48%) than controls (34%). In unadjusted analysis, L. iners-dominated and low-Lactobacillus profiles had higher odds of fibroid case status compared to other Lactobacillus-dominated profiles, however these results were not statistically significant. No association between vaginal microbiota and fibroids was observed after adjusting for race, HC and menstruation. Results were consistent when number of fibroids were considered. There was not a statistically significant association between longitudinal profiles of vaginal microbiota and uterine fibroids after adjustment for common confounders; however, the study was limited by small sample size.

Dysbiosis of vaginal and cervical microbiome is associated with uterine fibroids

Dysbiosis of the female reproductive tract is closely associated with gynecologic diseases. Here, we aim to explore the association between dysbiosis in the genital tract and uterine fibroids (UFs) to further provide new insights into UF etiology. We present an observational study to profile vaginal and cervical microbiome from 29 women with UFs and 38 healthy women, and 125 samples were obtained and sequenced. By comparing the microbial profiles between different parts of the reproductive tract, there is no significant difference in microbial diversity between healthy subjects and UF patients. However, alpha diversity of UF patients was negatively correlated with the number of fibroids. Increased Firmicutes were observed in both the cervical and vaginal microbiome of UF patients at the phylum level. In differential analysis of relative abundance, some genera were shown to be significantly enriched (e.g., Erysipelatoclostridium, Mucispirillum, and Finegoldia) and depleted (e.g., Erysipelotrichaceae UCG-003 and Sporolactobacillus) in UF patients. Furthermore, the microbial co-occurrence networks of UF patients showed lower connectivity and complexity, suggesting reduced interactions and stability of the cervical and vaginal microbiota in UF patients. In summary, our findings revealed the perturbation of microbiome in the presence of UFs and a distinct pattern of characteristic vaginal and cervical microbiome involved in UFs, offering new options to further improve prevention and management strategies.

Bacterial Vaginosis and Prospective Ultrasound Measures of Uterine Fibroid Incidence and Growth

BACKGROUND

Uterine fibroids often cause intolerable symptoms leading to invasive treatments, most commonly hysterectomy. Reproductive tract infections are hypothesized to influence uterine fibroid development, but few studies exist, especially for the highly prevalent condition bacterial vaginosis (BV). Both fibroids and BV have documented racial-ethnic disparities, with higher burden in Blacks.

METHODS

With prospective data from a community-based study (four standardized ultrasound examinations over 5 years) in young Black women, we examined baseline BV associations with fibroid incidence and growth. We computed adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for incidence comparing BV and no BV (Nugent score ≥7 vs. <7) using Cox proportional hazards models among 1027 women fibroid-free at baseline. Fibroid growth associations were based on linear mixed models estimating volume change between ultrasounds indexed to 18 months. We then expressed BV association as estimated percent difference in growth per 18 months, comparing exposed and unexposed.

RESULTS

There were n = 247 incident fibroids and 1181 growth measures; average fibroid growth per 18 months was a 78% (95% CI: 69 to 87) increase in volume. BV prevalence was 51% and not associated with fibroid incidence (aHR: 1.0, 95% CI: 0.80 to 1.4) or growth (estimated % difference in growth, -3% (95% CI: -12 to 6).

CONCLUSIONS

In this first study (to our knowledge) of ultrasound-monitored fibroid development and Nugent-assessed BV, we found no evidence to support the hypothesis that BV increased risk of fibroid incidence or growth or BV's role in the high burden of fibroids in Black women.

Bacterial Vaginosis-Associated Bacteria and Uterine Fibroids: A Nested Case-Control Study

BACKGROUND

Reproductive tract infections are hypothesized to influence uterine fibroid development, yet few studies have investigated the common condition of bacterial vaginosis (BV). The literature is currently limited to data using self-report of BV.

METHODS

We conducted a nested case-control study of 200 women (100 cases and 100 controls) from a large study of 23- to 35-year-old African American women, 1310 of whom were fibroid-free and prospectively followed up for 5 years to identify incident fibroids with standardized ultrasound examinations. We used quantitative polymerase chain reaction, an objective molecular method, to assess 9 BV-associated and 4 Lactobacillus species from vaginal swab specimens. We used hierarchical logistic regression to compute odds ratios and 95% confidence intervals to examine associations between bacterial species (both individually and grouped as (1) "optimal" Lactobacillus and (2) BV-associated species) with fibroid incidence and number. We also examined vaginal imbalance (quantitatively more BV-associated bacteria than optimal Lactobacilli).

RESULTS

Contrary to our hypothesis, we found no increase in fibroid incidence or number among women with more BV-associated bacteria. High imbalance (only BV-associated bacteria, no optimal Lactobacillus bacteria) was actually inversely associated with fibroid incidence (odds ratio, 0.38; 95% confidence interval, 0.17-0.81).

CONCLUSIONS

This is the first study of ultrasound-detected incident fibroids and molecular vaginal bacterial assessment. We found no evidence that BV-associated bacteria increase the risk of fibroid incidence or number.

Investigation on factors related to uterine fibroids in rural women of northern Anhui province

AIM

Given the increasing prevalence of hysteromyoma among the Chinese rural women of childbearing age, it is imperative that more attention should be given to researching risk factors that predispose women to this condition so that early preventive measures may be taken. Our study investigates potential risk factors for uterine fibroids such as participants' demographic characteristics (age, ethnicity, education), physiological characteristics (age at menarche, primiparous age), and the occurrence of several different female reproductive diseases (vaginitis, pelvic inflammatory disease).

METHODS

2200 rural women of reproductive age were screened from a cross-sectional study carried out in the northern Anhui province. Data were collected by questionnaire surveys, gynecological and laboratory examinations and were subjected to univariate and multivariate analysis to evaluate the risk factors for uterine fibroids.

RESULTS

Of the 2200 women, 440 had uterine fibroids. In general, women with endometriosis, ovarian cysts and early menarche were more likely to suffer from hysteromyoma. Factors including higher parity, late age of first childbirth, and a regular menstrual cycle were associated with the reduced risk of uterine fibroids.

CONCLUSIONS

Our findings indicate that parameters such as earlier age of menarche, early primiparous age, lower parity and a variety of female reproductive diseases were associated with an increased risk of uterine fibroids. These findings may be used to guide the formulation of effective prevention and intervention protocols to improve the reproductive health of rural women.