Maternal and foetal outcomes among pregnant women with vaginal dysbiosis: a systematic review and meta-analysis

Bacterial vaginosis (BV) is the most common gynecological condition in women of reproductive age. BV affects women during pregnancy and could lead to maternal-foetal outcomes that can be fatal for mothers and newborns. The aim of this review is to identify the different maternal and foetal outcomes among pregnant women with BV encountered worldwide and to highlight their prevalence. We search worldwide published articles that have recorded the prevalence of maternal-foetal outcomes among pregnant women with BV in the database Embase, PubMed, Web of Science, and Global Index Medicus from inception until January 2022. The meta-analysis was performed using a random-effects model. Sources of heterogeneity were investigated using subgroup analysis, while funnel plots and Egger tests were performed to assess publication bias. This review was registered in PROSPERO with the number CRD42022299498. A total of 8254 articles were found in the searched databases. After the exclusion of duplicated articles and others for multiple reasons, we finally obtained 26 articles that met all inclusion criteria. Worldwide, we recorded separately 22 maternal outcomes and 22 foetal outcomes among pregnant women with BV. When analyzing the different worldwide outcomes combined, there are 5 maternal-fetal outcomes that have been reported with the highest prevalence namely preterm birth, before 37 wGA (17.9% [95%CI= 13-23.3]), mechanical ventilation (15.2% [95%CI= 0-45.9]), low birth weight, less than 2500 g (14.2% [95%CI= 9.1-20.1]), premature rupture of membrane, before 37 wGA (13.2% [95%CI= 6.1-22.3]) and neonatal intensive care unit admission (11.2 % [95%CI= 0-53.5]). We also found that at the level of the WHO Region, South-East Asia records the highest prevalence of maternal-foetal outcomes (25.5 % [95%CI = 17.5-34.4]) followed by Africa with a prevalence of (24.6% [95%CI= 16.8-33.4]). At the diagnostic level, we obtained the greatest prevalence (37.2% [95%CI= 23-52.6]) for BV diagnosed with Amsel criteria, then blue test (31.7 % [95%CI= 8.4-60.6]). When considering gestation age, we obtained a high prevalence (29.6% [95%CI= 21.2-38.8]) among pregnant women with BV diagnosed in the third trimester of pregnancy. Even if BV is one of the most common vaginal conditions, the repartition of the type of maternal-foetal outcomes among pregnant women positive for BV is grandly disproportional among countries and continents.