# The Prevalence of Bacterial Vaginosis in Pregnant Women in Slovenia, Determined via Microscopy and Semi-Quantitative Relative Culture, and Its Association with Adverse Pregnancy Outcomes

## TL;DR

This study finds that a new diagnostic method for bacterial vaginosis in pregnant women better predicts adverse pregnancy outcomes compared to traditional microscopy.

## Contribution

The study introduces semi-quantitative relative culture with MALDI-TOF as a more effective diagnostic method for bacterial vaginosis in predicting adverse pregnancy outcomes.

## Key findings

- The prevalence of bacterial vaginosis was 6.5% via microscopy and higher (9.9% or 11.1%) using semi-quantitative relative culture.
- Semi-quantitative relative culture showed stronger associations with preterm birth and PPROM compared to microscopy.
- Semi-quantitative relative culture with MALDI-TOF identification demonstrated better clinical validity in predicting adverse outcomes.

## Abstract

Bacterial vaginosis (BV) is associated with various adverse pregnancy outcomes. It is usually diagnosed via microscopy. Semi-quantitative relative culture (SRC) was investigated as a complementary diagnostic method to determine the prevalence of BV and its association with preterm birth and preterm, premature rupture of membranes (PPROM) in pregnant women in Slovenia. We examined 3437 consecutive vaginal swabs from pregnant women during the five-year period and were able to link the results to 2531 pregnancy outcomes. The isolates were identified using MALDI-TOF, and the results were assessed by the relative amounts of Gardnerella vaginalis and lactobacilli according to two stringency criteria. The prevalence of BV was 6.5% via microscopy and was higher for SRC, 9.9% or 11.1%, depending on the stringency criteria. The association with adverse pregnancy outcomes was better when SRC was used, resulting in adjusted odds ratios of 1.76 (1.30 to 2.37) and 1.97 (1.38 to 2.82) for preterm birth and PPROM, respectively, with more stringent interpretation. Microscopically detected BV was not associated with either outcome. The clinical validity of SRC was demonstrated by its better correlation with adverse pregnancy outcomes in a large cohort of pregnant women. SRC with MALDI-TOF identification is a promising advancement of vaginal culture.