Vaginal Probiotics for Reproductive Health and Related Dysbiosis: Systematic Review and Meta-Analysis

Abstract

The use of probiotics in reproductive-related dysbiosis is an area of continuous progress due to the growing interest from clinicians and patients suffering from recurrent reproductive microbiota disorders. An imbalance in the natural colonization sites related to reproductive health-vaginal, cervicovaginal, endometrial, and pregnancy-related altered microbiota-could play a decisive role in reproductive outcomes. Oral and vaginal administrations are in continuous discussion regarding the clinical effects pursued, but the oral route is used and studied more often despite the need for further transference to the colonization site. The aim of the present review was to retrieve the standardized protocols of vaginal probiotics commonly used for investigating their microbiota modulation capacities. Most of the studies selected focused on treating bacterial vaginosis (BV) as the most common dysbiosis; a few studies focused on vulvovaginal candidiasis (VVC) and on pretreatment during in vitro fertilization (IVF). Vaginal probiotic doses administered were similar to oral probiotics protocols, ranging from ≥10⁷ CFU/day to 2.5 × 10¹⁰ CFU/day, but were highly variable regarding the treatment duration timing. Moderate vaginal microbiota modulation was achieved; the relative abundance of abnormal microbiota decreased and Lactobacillus species increased.

Keywords: IVF; VVC; bacterial vaginosis; reproductive dysbiosis; vaginal probiotics.

Figure 1

Intersection gap knowledge of reproductive system disorders, unexplained infertility, microbiome dysbiosis, and recurrent reproductive pathogenesis.

Figure 2

Vaginal probiotics Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Complementary oral probiotics PRISMA was previously performed [45].

Figure 3

Risk of bias graph of clinical trial (CT): review authors’ judgments about each item as percentages across all included studies.

Figure 4

Risk of bias summary of CT: authors’ judgments about each risk of bias item for each included study low risk (+, green circle), high risk (−, red circle), or unclear risk (?, yellow circle).

Figure 5

Effect of vaginal probiotics for modulation reduction in abnormal microbiota.

Figure 6

Effect of vaginal probiotics for modulation increase in Lactobacillus spp.