Vaginal Ureaplasma urealyticum or Mycoplasma hominis and preterm delivery in women with threatened preterm labor

Background: Amniotic fluid infection with Ureaplasma urealyticum or Mycoplasma hominis can cause chorioamnionitis and preterm birth. The aim of this study was to examine whether vaginal Ureaplasma urealyticum/Mycoplasma hominis colonization is predictive of preterm delivery in patients exhibiting signs of threatened preterm birth or those with asymptomatic short cervix. Methods: The present retrospective study, which was performed in a perinatal tertiary center, included patients carrying a singleton pregnancy who were referred to the emergency Ob/Gyn unit because of regular preterm uterine contractions and/or short cervical length (<20 mm) at 22-33 weeks of gestation, and in whom a vaginal U. urealyticum/M. hominis examination (Urea-arginine LYO-2, BioMerieux(R)) was performed. Univariate and multivariate analyses were performed to assess the association between vaginal U. urealyticum or M. hominis and chorioamnionitis or preterm delivery. Results: The median gestational age of the 94 enrolled patients was 29.9 weeks, and 54 (57%) of the patients were vaginal U. urealyticum/M. hominis-positive. The preterm delivery rate in the positive group was higher than in the negative group (53 versus 25%; p = .007). Vaginal U. urealyticum/M. hominis positivity was found to be an independent risk factor for preterm birth at <37 weeks of gestation (adjusted odds ratio = 4.0, 95% confidence interval, 1.1-15.3) in a multivariate analysis adjusted for age, history of preterm delivery and conization, gestational age, cervical length, presence of vaginal bleeding, vaginal fetal fibronectin and serum C-reactive protein at test. U. urealyticum/M. hominis positivity was not associated with delivery at Conclusion: A positive vaginal U. urealyticum/M. hominis culture is an independent predictive factor for preterm birth in patients with symptomatic threatened preterm labor and/or short cervix.