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

2019-04
BJOG : an international journal of obstetrics and gynaecology 127(2)
- 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

PubMed: 30932317
DOI: 10.1111/1471-0528.15675

Study Design

Type: Randomized Controlled Trial (RCT)
Population: Women aged 16 years or older recruited at 9-14 weeks' gestation
Methods: Randomised, double blind, placebo-controlled trial; participants randomly allocated to receive oral capsules of probiotic containing Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 each at 2.5 × 10^9 CFUs or placebo once daily from recruitment until the end of pregnancy
Blinding: Double-blind
Duration: from recruitment until the end of pregnancy

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.

Research Insights

Lactobacillus reuteri RC-14→Reduced Bacterial Vaginosis
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).
Effect
Neutral
Effect size
Small
Dose
2.5 × 10^9 colony-forming units (CFUs) once daily
Lactobacillus reuteri RC-14→Reduced Escherichia coli Colonization
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.
Effect
Neutral
Effect size
Small
Dose
2.5 × 10^9 colony-forming units (CFUs) once daily
Lactobacillus reuteri RC-14→Reduced Group B Streptococcus Colonization
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.
Effect
Neutral
Effect size
Small
Dose
2.5 × 10^9 colony-forming units (CFUs) once daily
Lactobacillus rhamnosus GR-1→Reduced Bacterial Vaginosis
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).
Effect
Neutral
Effect size
Small
Dose
2.5 × 10^9 colony-forming units (CFUs) once daily
Lactobacillus rhamnosus GR-1→Reduced Escherichia coli Colonization
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.
Effect
Neutral
Effect size
Small
Dose
2.5 × 10^9 colony-forming units (CFUs) once daily
Lactobacillus rhamnosus GR-1→Reduced Group B Streptococcus Colonization
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.
Effect
Neutral
Effect size
Small
Dose
2.5 × 10^9 colony-forming units (CFUs) once daily