Cervicovaginal detection of genital mycoplasmas is associated with preterm birth and low birth weight: a systematic review and multivariate meta-analysis of adverse pregnancy outcomes.

Abstract

Genital mycoplasmas (Mycoplasma genitalium, Mycoplasma hominis, and Ureaplasma species) are highly prevalent in women of reproductive age worldwide. The relevance of cervicovaginal detection in pregnancy remains controversial. This study aimed to assess their associations with adverse pregnancy outcomes. We conducted a systematic review and meta-analysis of observational studies published up to February 1, 2026, in MEDLINE, Embase, and the Cochrane Library. Eligible studies reported the presence of any genital mycoplasmas and at least one adverse pregnancy outcome. Four reviewers independently selected studies and extracted data. Pooled odds ratios and mean differences with 95% confidence intervals were calculated. Univariate and subgroup analyses were performed for primary and secondary outcomes and multivariate analysis for preterm birth. Sensitivity analyses restricted to cohort studies and cervicovaginal sampling were conducted. Of 11,957 records, 156 studies were included in meta-analysis. In sensitivity analyses excluding amniotic fluid and placental specimens, significant associations with spontaneous preterm birth and low birthweight remained for cervicovaginal samples. Cervicovaginal detection of Ureaplasma parvum was significantly associated with preterm birth (odds ratio, 1.63; confidence interval, 1.36-1.96). For Ureaplasma species, first-trimester detection showed stronger associations compared to second-trimester positivity (P=.044). Cervicovaginal Ureaplasma detection was also associated with low birthweight (odds ratio, 1.56; confidence interval, 1.33-1.83) and small for gestational age (odds ratio, 1.47; confidence interval, 1.19-1.80). Mycoplasma hominis showed significant associations with both preterm birth (adjusted odds ratio, 1.75; confidence interval, 1.21-2.53) and low birthweight (odds ratio, 1.81; confidence interval, 1.51-2.16) when detected in cervicovaginal samples. Associations between genital mycoplasmas and adverse pregnancy outcomes are not limited to intra-amniotic presence but are also observed with cervicovaginal detection. Given the observational nature of the available data and residual confounding, these associations should be interpreted cautiously and do not support routine screening or treatment. Cervicovaginal detection should be interpreted within the broader context of the vaginal microbial environment rather than as evidence of an isolated pathogenic effect.