High-density vaginal Ureaplasma urealyticum colonization as a risk factor for chorioamnionitis and preterm delivery

background The aim of this case control study was to investigate the influe nce of genital Ureaplasma urealyticum colonization on pregnancy outcome. Methods. One hundred and seventy-two women colonized with Ureaplasma urealy ticum without co-existing other infections and 123 women with negative cult ures for Ureaplasma urealyticum were enrolled. In a multivariate analysis t he influence of quantitative Ureaplasma urealyticum colonization level was determined. Results. Compared to the negative women increasing colonization with Ureapl asma urealyticum was associated with a significant decrease of birth weight (p < 0.0001) and gestational age (p < 0.0001) and with a significant incre ase of chorioamnionitis (p < 0.0001) and preterm delivery (p < 0.001). In a multivariate analysis high-density Ureaplasma urealyticum colonization was an independent risk factor for chorioamnionitis and preterm delivery, wher eas low colonization levels had no effect on an adverse outcome of pregnanc y. Conclusions. The degree of colonization with Ureaplasma urealyticum correla tes strongly with an adverse effect on pregnancy outcome.