Morphology assessed by transvaginal ultrasonography differs in patients inpreterm labor with vs. without bacterial vaginosis

Objective To determine whether cervical morphology in preterm labor patient s differs in the presence or absence of bacterial vaginosis. Design Observational study. Subjects One hundred and twelve consecutive patients with objectively confi rmed preterm labor admitted to a tertiary care centre were included in the study. Patients with placenta previa, active uterine bleeding or indication for an immediate delivery (e.g. severe pre-eclampsia or suspected fetal as phyxia), or severe fetal anomalies were excluded. Methods Transvaginal ultrasonography was used to measure cervical length an d internal of width. Bacterial vaginosis was diagnosed by Gram stain of a v aginal smear. Results A total of 36 patients (32%) had bacterial vaginosis. Cervical leng th in this group rues shorter than in patients with normal flora (mean 20.4 +/- 7.2 mm vs. 26.4 +/- 6.7 m-m, P = 0.0002), and more patients with bacte rial vaginosis had a dilated internal cervical os greater than or equal to 5 mm (67% vs. 30%, P = 0.001). There were no significant differences, howev er, in preterm delivery rate and birth weight between the two groups; the o verall preterm delivery rate was 40%. A cervical length < 25 mm was predict ive of preterm delivery (P = 0.001, RR 4.2, 95% Cl 2.8-9.7). Conclusions These data suggest that cervical change in preterm labor is mor e pronounced in patients with bacterial vaginosis but without a concomitant increase in the risk for preterm delivery. Despite this association, the c ervical length measured by transvaginal ultrasonography alone is a useful p redictor of preterm delivery, independent of the presence or absence of bac terial vaginosis.