Pre-Pregnancy Diet and Vaginal Environment in Caucasian Pregnant Women: An Exploratory Study.

Margherita Dall’Asta,Antonella Marangoni,Vittorio Sambri,Maria Carla Re,Sara Morselli,Francesca Danesi,Maria Federica Pedna,Claudio Foschi,Sara Zagonari,Giulia Patuelli,Luca Laghi

doi:10.3389/fmolb.2021.702370

Abstract

Vaginal microbes and their metabolic products have crucial functions, affecting local immunity development and maternal-fetal health. The composition of the vaginal microbiome can vary in response to various factors, including body mass index (BMI), and diet. In this study we get new insights into the vaginal ecosystem of Caucasian women (n = 24) at the first trimester of pregnancy, assessing whether pre-pregnancy diet can affect the structure of the vaginal environment in terms of bacterial composition and vaginal metabolite concentration. We characterized 1) the vaginal bacterial composition (Nugent score), 2) the vaginal metabolic profiles (1H-NMR spectroscopy), and 3) the dietary nutrient intake by means of a validated food frequency questionnaire. Pre-pregnancy BMI was negatively related to vaginal health status, indicating that women who begin pregnancy overweight/obese have a greater occurrence of vaginal dysbiosis during pregnancy. A lactobacilli-dominated vaginal microbiota was negatively associated with higher pre-pregnancy intake of animal-sourced protein. Conversely, a higher pre-pregnancy consumption of total carbohydrates and sugars seemed to be a protective factor for vaginal health. The vaginal environment of BV-women was characterized by higher levels of biogenic amines and organic acids, whereas higher levels of phenylpropionate and diverse amino acids were fingerprints of a healthy vaginal status. A significant association between a higher pre-pregnancy BMI and several dysbiosis-related vaginal metabolites was also found. Our study shed light on the role of pre-pregnancy BMI and diet on the vaginal environment during pregnancy, underlining the importance of limiting protein intake from animal foods to maintain a healthy lactobacilli-dominated microbiota.

Highlights

The cervicovaginal environment is composed by diverse microorganisms, creating dynamic and complex relationships with each other and with the host
To the best of our knowledge, this is the first report evaluating the impact of pre-pregnancy anthropometric and nutritional variables on the vaginal environment of Caucasian pregnant women
Since various factors can affect the structure of the vaginal microbiome, we excluded from the study all the women with conditions able to perturb the vaginal microbial composition

Summary

Introduction

The cervicovaginal environment is composed by diverse microorganisms, creating dynamic and complex relationships with each other and with the host. Microbes and their metabolic products have an important role in maintaining vaginal eubiosis: they can protect women from several infections, affect local immunity development and have an impact on maternal-fetal health (Oliver et al, 2020). In healthy reproductive-aged women, the vaginal microbiome is characterized by low bacterial diversity, being often dominated by different species of Lactobacillus genus (Smith and Ravel, 2017; Ceccarani et al, 2019). High concentrations of biogenic amines (e.g., putrescine, cadaverine, and trimethylamine) and short-chain fatty acids (SCFAs, especially acetate and succinate) with low levels of some amino acids (tyrosine, glutamate) are the most common metabolic fingerprints of BV (Parolin et al, 2018; Srinivasan et al, 2015; Vitali et al, 2015)

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