Paternal race and bacterial vaginosis during the first trimester of pregnancy

Novel risk factors associated with common vaginal infections: a nationwide primary healthcare cohort study

OBJECTIVE

To estimate the association between potential risk factors and common vaginal infections, using nationwide primary healthcare and other national register.

METHODS

An open cohort study consisting of 2 357 711 women aged 15-50 years (2001-2018) was conducted in Sweden. The outcomes were first event of vulvovaginal candidiasis (VVC) and bacterial vaginosis (BV) in relation to sociodemographic factors. Cox regression models were used. Sensitivity analyses including diabetes mellitus, contraceptive use, and cervical cancer were conducted.

RESULTS

The incidence rates per 1000 person-years for VVC and BV were 3.3 (95% CI 3.2-3.3) and 3.4 (95% CI 3.4-3.4), respectively. In the fully adjusted model, sociodemographic factors were significantly associated with both outcomes. Compared to Swedish-born women, women from Middle East/North Africa had the highest risk of VVC (HR 2.77, 95% CI, 2.72-2.83), followed by Africa (excluding North Africa) (HR 2.53, 95% CI, 2.45-2.61), and Latin America and the Caribbean (HR 2.18, 95% CI, 2.09-2.27). For BV, women from Latin America and the Caribbean had the highest risk (HR 1.83, 95% CI, 1.75-1.92).

CONCLUSION

This study presents novel risk factors associated with medically attended vaginal infections. Women from non-western countries seem to suffer disproportionately from these conditions.

The Association Between Vaginal Microbiota Dysbiosis, Bacterial Vaginosis, and Aerobic Vaginitis, and Adverse Pregnancy Outcomes of Women Living in Sub-Saharan Africa: A Systematic Review

Background: Previous studies have described the association between dysbiosis of the vaginal microbiota (VMB) and related dysbiotic conditions, such as bacterial vaginosis (BV) and aerobic vaginitis (AV), and various adverse pregnancy outcomes. There is limited overview of this association from countries in sub-Saharan Africa (SSA), which bear a disproportionally high burden of both vaginal dysbiotic conditions and adverse pregnancy outcomes. This systematic review assesses the evidence on the association between VMB dysbiosis, BV, and AV, and late adverse pregnancy outcomes in women living in SSA.

Methods: The Preferred Reporting Items for Systematic Review and Meta-Analysis Statement (PRISMA) guidelines were followed. Three databases [PubMed, Embase (Ovid), and Cochrane] were used to retrieve observational and intervention studies conducted in SSA that associated VMB dysbiosis, BV, or AV and preterm birth/labor/delivery, preterm rupture of membranes (PROM), low birthweight, small for gestational age, intrauterine growth restriction, intrauterine infection, intrauterine (fetal) death, stillbirth, perinatal death, or perinatal mortality.

Results: Twelve studies out of 693 search records from five SSA countries were included. One study identified a positive association between VMB dysbiosis and low birthweight. Despite considerable differences in study design and outcome reporting, studies reported an association between BV and preterm birth (7/9), low birthweight (2/6), PROM (2/4), intrauterine infections (1/1), and small for gestational age (1/1). None of the retrieved studies found an association between BV and pregnancy loss (5/5) or intrauterine growth retardation (1/1). At least two studies support the association between BV and PROM, low birthweight, and preterm birth in Nigerian pregnant women. No reports were identified investigating the association between AV and late adverse pregnancy outcomes in SSA.

Conclusion: Two of the included studies from SSA support the association between BV and PROM. The remaining studies show discrepancies in supporting an association between BV and preterm birth or low birthweight. None of the studies found an association between BV and pregnancy loss. As for the role of VMB dysbiosis, BV, and AV during pregnancy among SSA women, additional research is needed. These results provide useful evidence for prevention efforts to decrease vaginal dysbiosis and its contribution to adverse pregnancy outcomes in SSA.

Determinants of Vaginal Microbiota Composition

There is increasing evidence that the composition of a woman's vaginal microbiota significantly influences her sexual and reproductive health, including her risk of miscarriage, preterm birth, HIV and other sexually transmitted infections. Efforts to modulate the vaginal microbiota using antibiotic or probiotic therapy have shown limited lasting or reliable success. To explore the natural dynamics and causal pathways responsible for heterogeneity of vaginal microbiota composition we review the existing literature on its determinants, from the perspective of microorganism- and host-related factors. We then discuss how molecular approaches can be harnessed to advance our understanding of individual and population-level vaginal microbiota composition patterns. Work has been done to investigate determinants of microbial composition patterns in other body niches, but very little in the female genital tract so far. There is an urgent need to better understand vaginal microbiota composition patterns, across the lifespan, outside of the context of sexual health clinics, and in Sub-Saharan African women in whom vaginal microbiota composition may be a risk factor for HIV acquisition. More work is needed to clarify causal relationships between clinical symptoms, host genetic, host behavior, and molecular vaginal microbiota profiles. These insights will lay the groundwork for novel and targeted interventional approaches to improve women's sexual and reproductive health.

Pathogenesis of Bacterial Vaginosis: Discussion of Current Hypotheses

In April 2015, the Division of Microbiology and Infectious Diseases of the National Institute of Allergy and Infectious Diseases hosted an experts technical consultation on bacterial vaginosis (BV), where data regarding controversies over the pathogenesis of BV were discussed. The discussion on the epidemiology and pathogenesis of BV is presented here, and several hypotheses on its pathogenesis are critiqued. Rigorous hypothesis-driven studies are needed to ultimately determine the cause of BV. This information is vital for the prevention and control of this important infection and its adverse public health consequences.

Interpregnancy Interval and Anti-inflammatory Cervical Cytokines among Women with Previous Spontaneous Preterm Birth

OBJECTIVE

Both history of spontaneous preterm birth (sPTB) and shorter interpregnancy intervals (IPIs) increase the risk of recurrent sPTB. Mechanisms underlying the association between IPI and recurrent sPTB are unknown. We have previously demonstrated that higher concentrations of cervical anti-inflammatory cytokines are a risk factor for sPTB and upper genital tract inflammation. Here, we examine the association between IPI and cervical anti-inflammatory cytokines among women with previous sPTB.

PATIENTS AND METHODS

A prospective cohort of 73 women with previous sPTB and cervical interleukins (IL-4, IL-10, and IL-13) measured at < 16 weeks. Using the published principal factor analysis, the anti-inflammatory (ANTI) score was calculated. From our previous work, higher ANTI scores increase the subsequent risk of sPTB. IPI was the time from the previous birth to the conception of current pregnancy. Confounders included education level, marital status, gonorrhea, chlamydia, body mass index, race, and cigarette smoking. IPI and ANTI score were analyzed using univariable and multivariable analyses.

RESULTS

There was a significant negative linear relation between IPI and ANTI score (β = -0.075, p = 0.017). This persisted after adjustment for confounders (p = 0.02). As IPI decreases by 1 month, the ANTI-score-associated risk of sPTB increases approximately by 4%.

CONCLUSION

Among women with previous sPTB, there was a significant negative linear relation between IPI and ANTI score.

Prevalence of bacterial vaginosis in pregnant women in Maiduguri, North-Eastern Nigeria

OBJECTIVE

This study determined the prevalence and socio-demographic characteristics of bacterial vaginosis (BV) among pregnant women with abnormal vaginal discharge.

STUDY DESIGN

Descriptive cross-sectional study.

SETTING

University of Maiduguri Teaching Hospital.

MATERIALS AND METHODS

Vaginal swab samples and data on epidemiological risk factors were collected from 400 consecutive pregnant women with complaints of abnormal vaginal discharge. The data was analyzed using the SPSS 16.0 statistical software. Association between variables was compared by using the Chi-square (χ2 ) and Fisher's exact tests while P < 0.05 was considered significant at 95.0% confidence level.

RESULT

The prevalence of BV among pregnant women with abnormal vaginal discharge was 17.3%. Age 20-24 years, multigravidity, lack of western education and unemployment were associated with increased prevalence of BV. Yellowish, watery vaginal discharge (P = 0.001) was associated with BV. Dysuria, dyspareunia and lower abdominal tenderness were associated with BV (P = 0.001). Fifty three (77%) of patients had BV during the second trimester compared to 6 (9%) who had it in the 1 st trimester of pregnancy (P = 0.012).

CONCLUSION

The high prevalence of BV in this study may necessitate adequate screening of pregnant women with abnormal vaginal discharge in order to give appropriate treatment and avoid complications associated with it.

The global epidemiology of bacterial vaginosis: a systematic review

Bacterial vaginosis (BV) enhances the acquisition and transmission of a range of sexually transmitted infections including human immunodeficiency virus. This has made it more important to uncover the reasons why some populations have very high BV prevalences and others not. This systematic review describes the global epidemiology of BV. It summarizes data from peer-reviewed publications detailing the population prevalence of BV as diagnosed by a standardized and reproducible methodology-Nugent scoring system. BV variations between countries, and between ethnic groups within countries, are described. We evaluated 1692 English- and non-English-language articles describing the prevalence of BV using MEDLINE and the Web of Science databases. A total of 86 articles met our inclusion criteria. BV prevalences were found to vary considerably between ethnic groups in North America, South America, Europe, the Middle East, and Asia. Although BV prevalence is, in general, highest in parts of Africa and lowest in much of Asia and Europe, some populations in Africa have very low BV prevalences and some in Asia and Europe have high rates.

Maternal serum folate species in early pregnancy and lower genital tract inflammatory milieu

OBJECTIVE

We previously reported that elevated antiinflammatory cervical cytokines in early pregnancy were associated with spontaneous preterm birth. Our objective was to explore the relation between serum folate vitamers and the lower genital tract inflammatory milieu.

STUDY DESIGN

Pregnant women (n = 417) at <16 weeks' gestation had serum samples that were analyzed for folate species 5-methyltetrahydrofolate, 5-formyltetrahydrofolate, and cervical fluid that was assayed for cytokine concentrations. Patterns in proinflammatory cytokines (interleukin [IL]-1β, -6, -8, and -10; monocyte chemotactic protein-1) and antiinflammatory cytokines (IL-4, IL-10, IL-13) were identified with factor analysis.

RESULTS

After confounder adjustment, maternal serum 5-methyltetrahydrofolate concentrations had a strong negative association with elevated antiinflammatory scores; serum 5-formyltetrahydrofolate concentrations were associated positively with elevated antiinflammatory scores (both P < .05). Maternal folate was not associated with proinflammatory scores.

CONCLUSION

Maternal serum folate vitamers are associated with cervical cytokine concentrations, which suggests a possible mechanistic link between folate and preterm birth risk.

Lower genital tract inflammatory milieu and the risk of subsequent preterm birth: an exploratory factor analysis

The inflammatory milieu of the cervix may play a role in preventing intrauterine infection and subsequent preterm birth. The objectives of this study were to use exploratory factor analysis to discover the underlying structure of cytokines in the lower genital tract immunological milieu, and evaluate the association between the cytokine factors and risk of preterm birth. Women (n=613) enrolled in a prospective pregnancy cohort study in Pittsburgh, Pennsylvania had cervical cytokine concentrations assayed at <16 weeks and were followed for data on pregnancy outcomes. Principal factor analysis identified two primary cytokine patterns at <16 weeks gestation: Factor 1 (pro-inflammatory/immunomodulatory factor), which loaded highly on interleukin (IL)-1β, IL-6, IL-8, monocyte chemotactic protein-1, and IL-10, and Factor 2 (anti-inflammatory factor), which loaded heavily on IL-4, IL-10, and IL-13. Women in the highest tertile of anti-inflammatory cytokine factor scores at <16 weeks had an increased risk of spontaneous preterm birth (confounder-adjusted odds ratio [95% confidence interval]: 2.4 [1.1, 5.7]). There was no association between pro-inflammatory cytokine factor scores and preterm birth risk. These data support the hypothesis that increased concentrations of anti-inflammatory cytokines may represent a cervical immune milieu that permits subsequent microbial invasion of the uterus during pregnancy, leading to subsequent spontaneous preterm birth.

The aetiology of bacterial vaginosis

Bacterial vaginosis (BV) is the most common vaginal infection among women of childbearing age. This condition is notorious for causing severe complications related to the reproductive health of women. Five decades of intense research established many risk factors for acquisition of BV; however, because of the complexity of BV and lack of a reliable animal model for this condition, its exact aetiology remains elusive. In this manuscript, we use a historical perspective to critically review the development of major theories on the aetiology of BV, ultimately implicating BV-related pathogens, healthy vaginal microbiota, bacteriophages and the immune response of the host. None of these theories on their own can reliably explain the epidemiological data. Instead, BV is caused by a complex interaction of multiple factors, which include the numerous components of the vaginal microbial ecosystem and their human host. Many of these factors are yet to be characterized because a clear understanding of their relative contribution to the aetiology of BV is pivotal to the formulation of an effective treatment for and prophylaxis of this condition.

A genetic association study of maternal and fetal candidate genes that predispose to preterm prelabor rupture of membranes (PROM)

OBJECTIVE

We sought to determine whether maternal/fetal single-nucleotide polymorphisms (SNPs) in candidate genes are associated with preterm prelabor rupture of membranes (pPROM).

STUDY DESIGN

A case-control study was conducted in patients with pPROM (225 mothers and 155 fetuses) and 599 mothers and 628 fetuses with a normal pregnancy; 190 candidate genes and 775 SNPs were studied. Single locus/haplotype association analyses were performed; false discovery rate was used to correct for multiple testing (q* = 0.15).

RESULTS

First, a SNP in tissue inhibitor of metalloproteinase 2 in mothers was significantly associated with pPROM (odds ratio, 2.12; 95% confidence interval, 1.47-3.07; P = .000068), and this association remained significant after correction for multiple comparisons. Second, haplotypes for Alpha 3 type IV collagen isoform precursor in the mother were associated with pPROM (global P = .003). Third, multilocus analysis identified a 3-locus model, which included maternal SNPs in collagen type I alpha 2, defensin alpha 5 gene, and endothelin 1.

CONCLUSION

DNA variants in a maternal gene involved in extracellular matrix metabolism doubled the risk of pPROM.

Progress toward improved understanding of infection-related preterm birth

Current strategies to prevent infection-related preterm birth and its associated neonatal morbidities have had limited success. Improved understanding of the pathogen-host interactions underlying altered colonization of the lower genital tract is necessary before significant progress can be made. The application of novel diagnostic techniques such as broad range PCR and proteomic analysis contribute to our knowledge of the diversity and abundance of microbial species invading the amniotic cavity as well as the resultant inflammatory response. Preterm infants delivered following intrauterine infection may respond differently to subsequent infectious challenges in the neonatal intensive care unit.

Race of male sex partners and occurrence of bacterial vaginosis

BACKGROUND

Whether bacterial vaginosis (BV) is sexually transmitted is uncertain. Also it is unknown why BV is approximately twice as prevalent among black as among white women. An association of BV with a characteristic of the male sex partner, such as race, might support sexual transmission as well as account for the observed ethnic disparity in BV.

METHODS

Three thousand six hundred twenty nonpregnant women 15 to 44 years of age were followed quarterly for 1 year. At each visit, extensive questionnaire data and vaginal swabs for Gram's staining were obtained. The outcome was transition from BV-negative to positive (Nugent's score > or =7) in an interval of 2 consecutive visits.

RESULTS

BV occurred in 12.8% of 906 sexually active intervals to white women-24.8% of intervals when the woman reported a black partner and 10.7% when all partners were white. Among white women, there was a 2-fold increased risk for BV incidence with a black, compared with a white partner (risk ratio [RR] 2.3, 95% confidence interval 1.6-3.4; adjusted RR 2.2, 95% confidence interval 1.5-3.4), but differed according to condom use. In the presence of consistent condom use, the adjusted RR was 0.7 (0.3-2.4); it was 2.4 (1.0-6.2) in the presence of inconsistent use; and 2.7 (1.7-4.2) in the absence of condom use. Black women could not be studied, as there were insufficient numbers who reported only white male sex partners.

CONCLUSION

The association of BV occurrence with partner's race, and its blunting by condom use, suggests that BV may have a core group component and may be sexually transmitted.

Vaginal and oral microbes, host genotype and preterm birth

Preterm birth (PTB) is a leading cause of infant mortality and morbidity in the US and across the globe. Infection and associated inflammation are important initiators for PTB pathways; an estimated 40% of PTBs are attributed to amniochorionic-decidual or systemic inflammation. Historically, intrauterine infections have been implicated in PTB; recent evidence suggests that infections remote from the fetal site may also be causative. There is strong epidemiological evidence that bacterial vaginosis and periodontitis--two syndromes characterized by perturbations in the normal vaginal and oral bacterial microflora, respectively--are linked to infection-associated PTB. Oral and vaginal environments are similar in their bacterial microbiology; identical bacterial species have been independently isolated in periodontitis and bacterial vaginosis. Periodontitis and bacterial vaginosis also share many behavioral and sociodemographic risk factors suggesting a possible common pathophysiology. Genetic polymorphisms in host inflammatory responses to infection are shared between bacterial vaginosis, periodontitis and PTB, suggesting common mechanisms through which host genotype modify the effect of abnormal bacterial colonization on preterm birth. We review the state of knowledge regarding the risk of PTB attributable to perturbations in bacterial flora in oral and vaginal sites and the role of host genetics in modifying the risk of infection-related PTB. We posit that bacterial species that are common in perturbed vaginal and oral sites are associated with PTB through their interaction with the host immune system.

Bacterial vaginosis: a problematic infection from both a perinatal and neonatal perspective

Bacterial vaginosis (BV) infections are common in women of reproductive age and are easily diagnosed and treatable. Aside from being an annoyance when symptoms of discharge, odor, and pruritus occur in the gravid female, BV infections increase risk of late miscarriage, preterm labor, preterm premature rupture of membranes, and, consequently, preterm delivery. Antepartum and puerperal issues such as chorioamnionitis and endometritis are increased in the context of maternal BV. Moreover, the morbidities and mortality of preterm delivery are consequently increased as a result of BV during pregnancy. Although the pathology associated with BV appears to result from inflammation, more investigation is needed in terms of designing guidelines for appropriate screening and treatment for the prevention of adverse outcomes.

Maternal vitamin D deficiency is associated with bacterial vaginosis in the first trimester of pregnancy

Bacterial vaginosis (BV) is a highly prevalent vaginal infection that is associated with adverse pregnancy outcomes. Vitamin D exerts an influence on the immune system and may play a role in BV. The objective of this study was to examine the association between maternal vitamin D status and the prevalence of BV in early pregnancy. Women (n = 469) enrolled in a pregnancy cohort study at <16 wk underwent a pelvic examination and provided a blood sample for determination of serum 25-hydroxyvitamin D [25(OH)D]. BV was diagnosed using Gram-stained vaginal smears interpreted using the method of Nugent. Approximately 41% of women had BV (Nugent score 7-10) and 52% had a serum 25(OH)D concentration <37.5 nmol/L. The mean unadjusted serum 25(OH)D concentration was lower among BV cases (29.5 nmol/L; 95% CI: 27.1, 32.0) compared with women with normal vaginal flora (40.1 nmol/L; 95% CI: 37.0, 43.5; P < 0.001). BV prevalence decreased as vitamin D status improved (P < 0.001). Approximately 57% of the women with a serum 25(OH)D concentration <20 nmol/L had BV compared with 23% of women with a serum 25(OH)D concentration >80 nmol/L. There was a dose-response association between 25(OH)D and the prevalence of BV. The prevalence declined as 25(OH)D increased to 80 nmol/L, then reached a plateau. Compared with a serum 25(OH)D concentration of 75 nmol/L, there were 1.65-fold (95% CI: 1.01, 2.69) and 1.26-fold (1.01, 1.57) increases in the prevalence of BV associated with a serum 25(OH)D concentration of 20 and 50 nmol/L, respectively, after adjustment for race and sexually transmitted diseases. Vitamin D deficiency is associated with BV and may contribute to the strong racial disparity in the prevalence of BV.

Maternal vitamin D deficiency is associated with bacterial vaginosis in the first trimester of pregnancy

Bacterial vaginosis (BV) is a highly prevalent vaginal infection that is associated with adverse pregnancy outcomes. Vitamin D exerts an influence on the immune system and may play a role in BV. The objective of this study was to examine the association between maternal vitamin D status and the prevalence of BV in early pregnancy. Women (n = 469) enrolled in a pregnancy cohort study at <16 wk underwent a pelvic examination and provided a blood sample for determination of serum 25-hydroxyvitamin D [25(OH)D]. BV was diagnosed using Gram-stained vaginal smears interpreted using the method of Nugent. Approximately 41% of women had BV (Nugent score 7-10) and 52% had a serum 25(OH)D concentration <37.5 nmol/L. The mean unadjusted serum 25(OH)D concentration was lower among BV cases (29.5 nmol/L; 95% CI: 27.1, 32.0) compared with women with normal vaginal flora (40.1 nmol/L; 95% CI: 37.0, 43.5; P < 0.001). BV prevalence decreased as vitamin D status improved (P < 0.001). Approximately 57% of the women with a serum 25(OH)D concentration <20 nmol/L had BV compared with 23% of women with a serum 25(OH)D concentration >80 nmol/L. There was a dose-response association between 25(OH)D and the prevalence of BV. The prevalence declined as 25(OH)D increased to 80 nmol/L, then reached a plateau. Compared with a serum 25(OH)D concentration of 75 nmol/L, there were 1.65-fold (95% CI: 1.01, 2.69) and 1.26-fold (1.01, 1.57) increases in the prevalence of BV associated with a serum 25(OH)D concentration of 20 and 50 nmol/L, respectively, after adjustment for race and sexually transmitted diseases. Vitamin D deficiency is associated with BV and may contribute to the strong racial disparity in the prevalence of BV.