Role of Lactobacillus Species in the Intermediate Vaginal Flora in Early Pregnancy: A Retrospective Cohort Study

Alex Farr, Herbert Kiss, Michael Hagmann, Susanne Machal, Iris Holzer, Verena Kueronya, Peter Wolf Husslein, Ljubomir Petricevic, Alex Farr, Herbert Kiss, Michael Hagmann, Susanne Machal, Iris Holzer, Verena Kueronya, Peter Wolf Husslein, Ljubomir Petricevic

Abstract

Background: Poor obstetrical outcomes are associated with imbalances in the vaginal flora. The present study evaluated the role of vaginal Lactobacillus species in women with intermediate vaginal flora with regard to obstetrical outcomes.

Methods: We retrospectively analysed data from all women with singleton pregnancies who had undergone routine screening for asymptomatic vaginal infections at our tertiary referral centre between 2005 and 2014. Vaginal smears were Gram-stained and classified according to the Nugent scoring system as normal flora (score 0-3), intermediate vaginal flora (4-6), or bacterial vaginosis (7-10). Only women with intermediate vaginal flora were investigated. Women with a Nugent score of 4 were categorised into those with and without Lactobacilli. Follow-up smears were obtained 4-6 weeks after the initial smears. Descriptive data analysis, the Welch's t-test, the Fisher's exact test, and multiple regression analysis with adjustment for confounders were performed. Gestational age at delivery and birth weight were the outcome measures.

Results: At antenatal screening, 529/8421 women presented with intermediate vaginal flora. Amongst these, 349/529 (66%) had a Nugent score of 4, 94/529 (17.8%) a Nugent score of 5, and 86/529 (16.2%) a Nugent score of 6. Amongst those with a Nugent score of 4, 232/349 (66.5%) women were in the Lactobacilli group and 117/349 (33.5%) in the Non-Lactobacilli group. The preterm delivery rate was significantly lower in the Lactobacilli than in the Non-Lactobacilli group (OR 0.34, CI 0.21-0.55; p<0.001). Mean birth weight was 2979 ± 842 g and 2388 ± 1155 g in the study groups, respectively (MD 564.12, CI 346.23-781.92; p<0.001). On follow-up smears, bacterial vaginosis rates were 9% in the Lactobacilli and 7.8% in the Non-Lactobacilli group.

Conclusions: The absence of vaginal Lactobacillus species and any bacterial colonisation increases the risks of preterm delivery and low birth weight in women with intermediate vaginal flora in early pregnancy.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist..

Figures

Fig 1. Birth weight (A) and gestational…
Fig 1. Birth weight (A) and gestational age (B) at delivery in 529 women with intermediate vaginal flora.
Fig 2. Vaginal follow-up smears of the…
Fig 2. Vaginal follow-up smears of the 349 women with intermediate vaginal flora and a Nugent score of 4 at the initial screening.

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