Mycoplasma and ureaplasma infection and male infertility: a systematic review and meta-analysis

The relationship between mycoplasma and ureaplasma infection and male infertility has been studied widely; however, results remain controversial. This meta-analysis investigated the association between genital ureaplasmas (Ureaplasma urealyticum, Ureaplasma parvum) and mycoplasmas (Mycoplasma hominis, Mycoplasma genitalium), and risk of male infertility. Differences in prevalence of ureaplasma and mycoplasma infection between China and the rest of the world were also compared. Study data were collected from PubMed, Embase and the China National Knowledge Infrastructure. Summary odds ratio (OR) with 95% confidence interval (CI) was applied to assess the relationship. Heterogeneity testing and publication bias testing were also performed. A total of 14 studies were used: five case control studies with 611 infertile cases and 506 controls featuring U. urealyticum infection, and nine case-control studies with 2410 cases and 1223 controls concerning M. hominis infection. Two other infection (U. parvum and M. genitalium) were featured in five and three studies, respectively. The meta-analysis results indicated that U. parvum and M. genitalium are not associated with male infertility. However, a significant relationship existed between U. urealyticum and M. hominis and male infertility. Comparing the global average with China, a significantly higher positive rate of U. urealyticum, but a significantly lower positive rate of M. hominis, was observed in both the infertile and control groups in China.