The Associations of Genital Mycoplasmas with Female Infertility and Adverse Pregnancy Outcomes: a Systematic Review and Meta-analysis

The roles of genital mycoplasmas including Mycoplasma genitalium ( M. genitalium ), Mycoplasma hominis ( M. hominis ), Ureaplasma urealyticum ( U. urealyticum ), and Ureaplasma parvum ( U. parvum ) in reproductive diseases are equivocal. To investigate whether genital mycoplasmas are risk factors of female infertility and adverse pregnancy outcomes, we performed a systematic review and meta-analysis. Electronic databases were searched for related studies. A random-effects model or fixed-effects model was employed to generate forest plots. Pooled odd ratios (ORs) with 95% confidence intervals (CIs) were applied to measure the strength of associations. Meanwhile, heterogeneity was evaluated by H statistic and I 2 statistic, and publication bias was explored by funnel plots based on Egger’s test and Begg’s test. The search yielded 2054 relevant records, and 35 articles were ultimately included for meta-analysis. M. genitalium was a significant risk factor for female infertility (OR, 13.03 [95% CI, 3.46–48.98]) and preterm birth (PTB) (OR, 1.81 [95% CI, 1.17–2.80]), but not for spontaneous abortion (SA) (OR, 0.58 [95% CI, 0.25–1.35]). M. hominis can significantly increase the potential risk of female infertility (OR, 1.56 [95% CI, 1.02–2.38]), SA (OR, 9.14 [95% CI, 4.14–20.18]), stillbirth (OR, 3.98 [95% CI, 1.39–11.36]), and premature rupture of membranes (PROM) (OR, 1.79 [95% CI, 1.26–2.55]), but was not associated with PTB (OR, 1.29 [95% CI, 0.78–2.15]). U. urealyticum had no significant risk effect on female infertility (OR, 0.68 [95% CI, 0.42–1.11]). Coinfections of M. hominis and Ureaplasma were significantly associated with female infertility, SA, and stillbirth, but not with PROM. On the basis of current evidences, this meta-analysis supports that M. genitalium is a risk factor for female infertility and PTB; M. hominis is a potential risk factor for female infertility, SA, stillbirth, and PROM; U. urealyticum has no significant association with female infertility; and the relationship of U. parvum with female infertility and adverse pregnancy outcomes needs to be paid more attention to and remains to be further revealed.