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Effects of oral probiotic supplements on vaginal microbiota during pregnancy: a randomised, double-blind, placebo-controlled trial with microbiome analysis

Research output: Contribution to journalArticle

S Husain, J Allotey, Z Drymoussi, M Wilks, B M Fernandez-Felix, A Whiley, J Dodds, S Thangaratinam, C McCourt, E M Prosdocimi, W G Wade, B M de Tejada, J Zamora, K Khan, M Millar

Original languageEnglish
Pages (from-to)275-284
Number of pages10
Issue number2
Early online date1 Apr 2019
Publication statusPublished - 1 Jan 2020

Bibliographical note

© 2019 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists.

King's Authors


OBJECTIVE: To determine the effects on the vaginal microbiota of an oral probiotic preparation administered from early pregnancy.

DESIGN: Randomised, double blind, placebo-controlled trial.

SETTING: Four maternity units in the UK.

POPULATION: Women aged 16 years or older recruited at 9-14 weeks' gestation.

METHODS: Participants were randomly allocated to receive oral capsules of probiotic containing Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 each at 2.5 × 109 colony-forming units (CFUs) or placebo once daily from recruitment until the end of pregnancy.

MAIN OUTCOME MEASURE: Rates of bacterial vaginosis (BV, defined as Nugent score ≥7) at 18-20 weeks' gestation compared by logistic regression adjusted for possible confounders.

RESULTS: The primary analysis included 78% (238/304) of participants who initially consented (probiotic group 123, placebo group 115). Of these participants, 95% (227/238) reported an intake of 93% or more of the required number of capsules. The rates of BV did not differ between groups at 18-20 weeks' gestation (15% (19/123) in the probiotic group vs. 9% (10/115) in the placebo group, adjusted odds ratio 1.82, 95% confidence interval 0.64-5.19). There were also no differences between the groups in the proportion of women colonised with the probiotic strains, Escherichia coli, Group B streptococci or other vaginal microbiota. There were no differences in the alpha diversity or composition of the bacterial communities between or within the probiotic and placebo groups at 9-14 and 18-20 weeks' gestation.

CONCLUSIONS: Oral probiotics taken from early pregnancy did not modify the vaginal microbiota.

TWEETABLE ABSTRACT: The oral probiotic preparation used in this study does not prevent BV in pregnant women.

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