Associations between microbial presence in follicular fluid with IVF outcomes: a systematic review and meta-analysis

Purpose The aim of the study was to synthesize disparate studies to investigate potential impact of microbial presence in FF of infertile women on IVF outcomes. Methods Following preliminary searches to find medical subject heading (MeSH) terms plus free terms, a systematic search was performed in the PubMed, Cochrane Library, Embase, Web of Science, and Clinicaltrials.gov databases from January 10, 2022, to July 5, 2023. Data collected for each study were analyzed using RevMan 5.4 software available on the Cochrane website. Results After correcting for contamination from the vagina, the FFs of 289 women were detected positively by microbial culture and identification, ELISA, and IPA. The pregnancy rate of the FF-positive group was significantly lower than the FF-negative group (19.7% vs. 32.2%) and (OR: 0.57, 95% CI: 0.28–1.14, P =0.11; I 2 =56%) while the fertilization rate was almost equal (60.0% vs. 62.0%) and (OR: 1.03, 95% CI: 0.88–1.20, P =0.72; I 2 =0%). Evidence quality was very low. Conclusions The different species of microorganisms in FF of infertile women may have different effects on IVF outcomes. The Lactobacillus spp. may have a positive effect, while other microorganisms may have the opposite effect.