BackgroundBacterial vaginosis (BV), an alteration of vaginal flora involving a decrease in Lactobacilli and predominance of anaerobic bacteria, is among the most common cause of vaginal complaints for women of childbearing age. It is well known that BV has an influence in acquisition of certain genital infections. However, association between BV and cervical human papillomavirus (HPV) infection has been inconsistent among studies. The objective of this meta-analysis of published studies is to clarify and summarize published literature on the extent to which BV is associated with cervical HPV infection.MethodsMedline and Web of Science were systematically searched for eligible publications until December 2009. Articles were selected based on inclusion and exclusion criteria. After testing heterogeneity of studies, meta-analysis was performed using random effect model.ResultsTwelve eligible studies were selected to review the association between BV and HPV, including a total of 6,372 women. The pooled prevalence of BV was 32%. The overall estimated odds ratio (OR) showed a positive association between BV and cervical HPV infection (OR, 1.43; 95% confidence interval, 1.11-1.84).ConclusionThis meta-analysis of available literature resulted in a positive association between BV and uterine cervical HPV infection.

It needs to be recognized that most inferences drawn in our study rely on a limited number of studies, potentially, endangering the generalizability of our findings. Moreover, all studies on cause of infertility in relation to BV included had a cross-sectional design and, therefore, do not allow for causal inferences. Still, there is strong circumstantial evidence that supports a causal link between BV and tubal infertility. Studies with a longitudinal design, on the other hand, strongly support a relation between BV and early pregnancy loss. Unfortunately, no study looked beyond first trimester fetal loss, although it is plausible that the high preterm birth rates with IVF are, at least, in part attributable to BV.

ObjectiveBacterial vaginosis (BV), the most common vaginal disorder among women of reproductive age, has been suggested as co-factor in the development of cervical cancer. Previous studies examining the relationship between BV and cervical intra-epithelial neoplasia (CIN) provided inconsistent and conflicting results. The aim of this study is to clarify the association between these two conditions.MethodsA systematic review and meta-analysis were conducted to summarize published literature on the association between BV and cervical pre-cancerous lesions. An extensive search of electronic databases Medline (Pubmed) and Web of Science was performed. The key words ‘bacterial vaginosis’ and ‘bacterial infections and vaginitis’ were used in combination with ‘cervical intraepithelial neoplasia’, ‘squamous intraepithelial lesions’, ‘cervical lesions’, ‘cervical dysplasia’, and ‘cervical screening’. Eligible studies required a clear description of diagnostic methods used for detecting both BV and cervical pre-cancerous lesions. Publications were included if they either reported odds ratios (OR) and corresponding 95% confidence intervals (CI) representing the magnitude of association between these two conditions, or presented data that allowed calculation of the OR.ResultsOut of 329 articles, 17 cross-sectional and 2 incidence studies were selected. In addition, two studies conducted in The Netherlands, using the national KOPAC system, were retained. After testing for heterogeneity and publication bias, meta-analysis and meta-regression were performed, using a random effects model. Although heterogeneity among studies was high (χ2 = 164.7, p<0.01, I2 = 88.5), a positive association between BV and cervical pre-cancerous lesions was found, with an overall estimated odds ratio of 1.51 (95% CI, 1.24–1.83). Meta-regression analysis could not detect a significant difference between studies based on BV diagnosis, CIN diagnosis or study population.ConclusionsAlthough most studies were cross-sectional and heterogeneity was high, this meta-analysis confirms a connection between BV and CIN.

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Currently, human papillomavirus (HPV) research focuses on HPV infection in adults and sexual transmission. Data on HPV infection in children are slowly becoming available. It is a matter of debate whether mother-to-child transmission of HPV is an important infection route and whether children born to HPV-positive mothers are at a higher risk of HPV infection compared with children born to HPV-negative mothers. The objective of this meta-analysis is to summarize the published literature on the extent to which genital HPV infection is vertically transmitted from mother to child. Medline, Web of Science, and CINAHL were searched for eligible reports published before January 2011. Differences in the risk of HPV infection between newborns from HPV-positive and HPV-negative mothers were pooled using a random-effects model. Twenty eligible studies, including 3128 women/children pairs, fulfilled the selection criteria. High heterogeneity could be found (I=96%). The overall estimated risk difference was 33% (95% confidence interval: 22-44%). On restricting to high-risk HPV-positive mothers only (n=4; women=231), the difference in risk was 45% (95% confidence interval: 33-56%). The heterogeneity was found to be low (I=15%). This meta-analysis indicates a significantly higher risk for children born to HPV-positive mothers to become HPV positive themselves. Plausible explanations include vertical transmission of HPV during pregnancy and/or birth or a higher infection rate during early nursing from mother to child. More research is required to gain an insight into the precise mode of transmission and the clinical effects of infection on the child.