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

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

Journal: BJOG : an international journal of obstetrics and gynaecology 2020;127(2):275-284

PMID: 30932317

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Plain Language Summary

Bacterial vaginosis (BV), in which the normally dominant lactobacilli of the vagina are replaced with anaerobic bacteria, is associated with adverse pregnancy outcomes including preterm birth (PTB). Antibiotics are effective in eradicating BV during pregnancy and are recommended for use in symptomatic pregnant women. The aim of this study was to determine the biological effects of oral probiotics on the vaginal microbiota and the feasibility of conducting a full-scale trial of oral probiotic supplementation of women from early pregnancy to delivery in preventing PTB. This study is a pragmatic randomised, double-blind, placebo-controlled trial with microbiome analysis. The study recruited pregnant women in early pregnancy who were randomised to one of the two groups: intervention or control. Results show that daily oral administration of probiotics from early pregnancy did not affect the prevalence of BV, common neonatal pathogens or alter the composition of the vaginal microbiota at 18–20 weeks’ gestation. Authors conclude that their findings did not show evidence of an effect of oral probiotics on the vaginal microbiota in pregnancy.

Abstract

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 × 10 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.

Address: Barts and the London School of Medicine and Dentistry, Blizard Institute, Queen Mary University of London, London, UK.; Neonatal Unit, Homerton University Hospital NHS Foundation Trust, London, UK.; Women's Health Research Unit, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.; Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.; Barts Health NHS Trust, London, UK.; CIBER Epidemiology and Public Health (CIBERESP), Madrid, Spain.; Clinical Biostatistics Unit, Hospital Ramon y Cajal (IRYCIS), Madrid, Spain.; City University of London, University of London, London, UK.; Centre for Host-Microbiome Interactions, King's College London, London, UK.; Department of Obstetrics and Gynaecology, Faculty of Medicine, University Hospitals of Geneva, Geneva, Switzerland.

DOI: 10.1111/1471-0528.15675

Patient Centred Factor

Triggers: Probiotics

Physical Environment

Infectious Agents

Clinical Imbalances

Gastro-intestinal

Modifiable Lifestyle Factors

Diet

Jadad Score

Allocation Concealment

Yes

Nutrition Evidence Keywords

Pregnancy Microbiota Probiotic

Bioactive Substances

Probiotics

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MeSH Terms: Adult, Double-Blind Method, Female, Humans, Limosilactobacillus reuteri, Lacticaseibacillus rhamnosus, Microbiota, Pregnancy, Pregnancy Complications, Infectious, Pregnancy Trimester, First, Probiotics, Vagina, Vaginosis, Bacterial, Young Adult