Recent Insights on the Maternal Microbiota: Impact on Pregnancy Outcomes

Simone, Nicoletta Di; Ortiz, Amparo Santamaría; Specchia, Monia; Tersigni, Chiara; Villa, Paola; Gasbarrini, Antonio; Scambia, Giovanni; D’Ippolito, Silvia

doi:10.3389/fimmu.2020.528202

Cited by 76 publications

(62 citation statements)

References 99 publications

(135 reference statements)

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“…It is well known that the vaginal bacterial composition plays a crucial role in maternal-fetal health (Fox and Eichelberger, 2015;Nelson et al, 2016). Indeed, healthy pregnancies are characterized by low numbers of vaginal bacterial communities dominated by Lactobacillus, whereas reduced lactobacilli with an increased bacterial diversity are associated with pregnancy-related complications and preterm birth (Prince et al, 2014;Di Simone et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

New Insights into Vaginal Environment During Pregnancy

Marangoni

Laghi

Zagonari

et al. 2021

Front. Mol. Biosci.

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During pregnancy, the vaginal ecosystem undergoes marked changes, including a significant enrichment with Lactobacillus spp. and profound alterations in metabolic profiles. A deep comprehension of the vaginal environment may shed light on the physiology of pregnancy and may provide novel biomarkers to identify subjects at risk of complications (e.g., miscarriage, preterm birth). In this study, we characterized the vaginal ecosystem in Caucasian women with a normal pregnancy (n = 64) at three different gestational ages (i.e., first, second and third trimester) and in subjects (n = 10) suffering a spontaneous first trimester miscarriage. We assessed the vaginal bacterial composition (Nugent score), the vaginal metabolic profiles (1H-NMR spectroscopy) and the vaginal levels of two cytokines (IL-6 and IL-8). Throughout pregnancy, the vaginal microbiota became less diverse, being mainly dominated by lactobacilli. This shift was clearly associated with marked changes in the vaginal metabolome: over the weeks, a progressive reduction in the levels of dysbiosis-associated metabolites (e.g., biogenic amines, alcohols, propionate, acetate) was observed. At the same time, several metabolites, typically found in healthy vaginal conditions, reached the highest concentrations at the end of pregnancy (e.g., lactate, glycine, phenylalanine, leucine, isoleucine). Lower levels of glucose were an additional fingerprint of a normal vaginal environment. The vaginal levels of IL-6 and IL-8 were significantly associated with the number of vaginal leukocytes, as well as with the presence of vaginal symptoms, but not with a condition of dysbiosis. Moreover, IL-8 concentration seemed to be a good predictor of the presence of vaginal Candida spp. Cytokine concentrations were negatively correlated to lactate, serine, and glycine concentrations, whereas the levels of 4-hydroxyphenyllactate, glucose, O-acetylcholine, and choline were positively correlated with Candida vaginal loads. Finally, we found that most cases of spontaneous abortion were associated with an abnormal vaginal microbiome, with higher levels of selected metabolites in the vaginal environment (e.g., inosine, fumarate, xanthine, benzoate, ascorbate). No association with higher pro-inflammatory cytokines was found. In conclusion, our analysis provides new insights into the pathophysiology of pregnancy and highlights potential biomarkers to enable the diagnosis of early pregnancy loss.

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Section: Introductionmentioning

confidence: 99%

New Insights into Vaginal Environment During Pregnancy

Marangoni

Laghi

Zagonari

et al. 2021

Front. Mol. Biosci.

View full text Add to dashboard Cite

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“…It is well known that the vaginal bacterial composition plays a crucial role in maternal-fetal health ( Nelson et al, 2016 ). Healthy pregnancies are usually characterized by a lactobacilli-dominated vaginal microbiota, whereas reduced lactobacilli with increased bacterial diversity are associated with pregnancy-related complications and preterm birth ( Di Simone et al, 2020 ).…”

Section: Discussionmentioning

confidence: 99%

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

Dall’Asta

Laghi

Morselli

et al. 2021

Front. Mol. Biosci.

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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.

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“…Be it as may, increasing evidence is piling up that estrogen plays a critical role in the maintenance of the vaginal microbiome. Among physiological alterations that occur during pregnancy to adapt to pregnancy-specific physiological processes in mother and fetus, one of the important physiological changes would be increased estrogen level, which directly impacts the vaginal microbiome [50][51][52][53]. The rising level of estrogen promotes glycogen synthesis within the vaginal epithelium, which in turn selectively enriches the growth of Lactobacillus spp.…”

Section: The Development Of the Vaginal Microbiome: How Does It Change Throughout A Woman's Life?mentioning

confidence: 99%

Finding a Balance in the Vaginal Microbiome: How Do We Treat and Prevent the Occurrence of Bacterial Vaginosis?

et al. 2021

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Bacterial vaginosis (BV) has been reported in one-third of women worldwide at different life stages, due to the complex balance in the ecology of the vaginal microbiota. It is a common cause of abnormal vaginal discharge and is associated with other health issues. Since the first description of anaerobic microbes associated with BV like Gardnerella vaginalis in the 1950s, researchers have stepped up the game by incorporating advanced molecular tools to monitor and evaluate the extent of dysbiosis within the vaginal microbiome, particularly on how specific microbial population changes compared to a healthy state. Moreover, treatment failure and BV recurrence rate remain high despite the standard antibiotic treatment. Consequently, researchers have been probing into alternative or adjunct treatments, including probiotics or even vaginal microbiota transplants, to ensure successful treatment outcomes and reduce the colonization by pathogenic microbes of the female reproductive tract. The current review summarizes the latest findings in probiotics use for BV and explores the potential of vaginal microbiota transplants in restoring vaginal health.

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Recent Insights on the Maternal Microbiota: Impact on Pregnancy Outcomes

Abstract: personalized therapies for the prevention of obstetric complications and personalized treatments through nutritional, microbiotic, or pharmaceutical interventions.

Cited by 76 publications

References 99 publications

New Insights into Vaginal Environment During Pregnancy

New Insights into Vaginal Environment During Pregnancy

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

Finding a Balance in the Vaginal Microbiome: How Do We Treat and Prevent the Occurrence of Bacterial Vaginosis?

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