An exploratory study of associations with spontaneous preterm birth in primigravid pregnant women with a normal cervical length

Sarmento, Stéphanno Gomes Pereira; Moron, Antônio Fernandes; Forney, Larry J.; Hatanaka, Alan Roberto; Carvalho, Francisco Herlânio Costa; França, Marcelo Santucci; Hamamoto, Tatiana Emy Nishimoto Kawanami; Mattar, Rosiane; Linhares, Iara Moreno; Minis, Evelyn; Sañudo, Adriana; Sabino, Éster Cerdeira; Rudge, Marilza Vieira Cunha

doi:10.1080/14767058.2021.1879786

Cited by 6 publications

(10 citation statements)

References 27 publications

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“…This was also demonstrated by Kindinger et al., who reported that the vaginal microbiome dominated by L. iners at 16 weeks of gestation is a risk factor for both a short cervix and early PTB (<34 weeks), whereas L. crispatus dominance is protective against PTB in a more ethnically diverse cohort ( Kindinger et al., 2017 ). Recent studies from different countries also showed a significant association between L. iners and an increased prevalence of PTB ( Elovitz et al., 2019 ; Aslam et al., 2020 ; Goodfellow et al., 2021 ; Kumar et al., 2021 ; Payne et al., 2021 ; Sarmento et al., 2021 ). However, several studies reported no significant association between L. iners and PTB ( Callahan et al., 2017 ; Blostein et al., 2020 ; Witkin et al., 2021 ).…”

Section: Iners and Women Diseasesmentioning

confidence: 88%

“…Earlier studies confirmed that high estradiol levels and the consequent high glycogen levels in the vagina during pregnancy result in stronger vaginal acidification, thereby promoting the prevalence of Lactobacillu s species as gestation progresses ( Aagaard et al., 2012 ; Basavaprabhu et al., 2020 ). However, many studies have indicated that the L. iners -dominated vaginal microbiome was more likely to shift towards dysbiosis during pregnancy ( Mls et al., 2019 ; Kumar et al., 2021 ; Sarmento et al., 2021 ). In our previous study, we found that the abundance of L. iners decreased significantly in the second and third trimester, whereas that of L. crispatus increased in the second trimester compared with the first trimester in healthy pregnant women ( Zheng et al., 2019 ).…”

Section: Iners and Women Diseasesmentioning

confidence: 99%

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Contribution of Lactobacillus iners to Vaginal Health and Diseases: A Systematic Review

Zheng

Guo

Wang

et al. 2021

Front. Cell. Infect. Microbiol.

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Lactobacillus iners, first described in 1999, is a prevalent bacterial species of the vaginal microbiome. As L. iners does not easily grow on de Man-Rogosa-Sharpe agar, but can grow anaerobically on blood agar, it has been initially overlooked by traditional culture methods. It was not until the wide application of molecular biology techniques that the function of L. iners in the vaginal microbiome was carefully explored. L. iners has the smallest genome among known Lactobacilli and it has many probiotic characteristics, but is partly different from other major vaginal Lactobacillus species, such as L. crispatus, in contributing to the maintenance of a healthy vaginal microbiome. It is not only commonly present in the healthy vagina but quite often recovered in high numbers in bacterial vaginosis (BV). Increasing evidence suggests that L. iners is a transitional species that colonizes after the vaginal environment is disturbed and offers overall less protection against vaginal dysbiosis and, subsequently, leads to BV, sexually transmitted infections, and adverse pregnancy outcomes. Accordingly, under certain conditions, L. iners is a genuine vaginal symbiont, but it also seems to be an opportunistic pathogen. Further studies are necessary to identify the exact role of this intriguing species in vaginal health and diseases.

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Section: Iners and Women Diseasesmentioning

confidence: 88%

Section: Iners and Women Diseasesmentioning

confidence: 99%

Contribution of Lactobacillus iners to Vaginal Health and Diseases: A Systematic Review

Zheng

Guo

Wang

et al. 2021

Front. Cell. Infect. Microbiol.

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“…Importantly, clustering by CST allows identification of vaginal microbiota dominated by L. iners (CST III), which is often found in the vaginal microbiota of women with bacterial vaginosis (BV) (Zozaya-Hinchliffe et al, 2010;Srinivasan et al, 2012;Petrova et al, 2017). As we learn more about the functional and genomic diversity of L. iners (Macklaim et al, 2013), it is becoming evident that grouping all L. iners-dominated vaginal microbiota with other Lactobacillusdominated CSTs may not be appropriate as it might not confer the same protection against adverse reproductive health outcomes (Van Houdt et al, 2018;Sarmento et al, 2021). It is not entirely surprising that there is a high degree of similarity between the composition of the vaginal and genitourinary microbiota using CSTs.…”

Section: Cst Concordancementioning

confidence: 99%

Assessing the Concordance Between Urogenital and Vaginal Microbiota: Can Urine Specimens Be Used as a Proxy for Vaginal Samples?

Brown

Robinson

Shardell

et al. 2021

Front. Cell. Infect. Microbiol.

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BackgroundThe vaginal microbiota play a key role in defense against reproductive tract infections; however, many population-based women’s health studies do not collect vaginal samples. Molecular examinations of urine samples have revealed common vaginal bacteria. We sought to assess the extent that community state type assignments of archived random-catch and clean-catch urine samples agreed with the paired vaginal samples in both reproductive-age and peri/post-menopausal women.ResultsUsing archived samples, we evaluated the microbiota concordance among women in three studies: two with paired mid-vaginal/random-catch urine (N=91 reproductive-age participants and N=13 peri/post-menopausal participants), and one with paired mid-vaginal/clean-catch urine (N=99 reproductive-age participants). Microbiota composition was characterized by sequencing amplicons of the 16S rRNA gene V3-V4 regions and assigned to community state types. Similarity of paired samples was gauged using agreement of community state types and Yue-Clayton θ indices. Analysis of Composition of Microbiomes II indicated which taxa were differently relatively abundant in paired vaginal and urine samples. In reproductive-age women, random-catch and clean-catch urines were 89.0% and 86.9% concordant on five community state types with paired mid-vaginal swabs, and Kappa statistics indicated almost perfect agreement (κrandom-catch=.85, κclean-catch=.81, p<0.0001). A small number of pairs of samples were discordant (23/190, 12%), and discordant pairs tended to be between samples classified to L. iners-dominated and/or low-Lactobacillus states. Concordance and agreement remained similar when dichotomizing the microbiota to Lactobacillus-dominated versus low-Lactobacillus microbiota, as well as when evaluating separately the three subtypes of the low-Lactobacillus community state type IV. Median similarity of paired urine/vaginal samples was high (θrandom-catch=.85, θclean-catch=.88), and a comparison of the random-catch and clean-catch similarity scores showed no significant difference (p=.80). Concordance and similarity were lower for peri/post-menopausal women, but agreement remained substantial (76.9% concordant, κrandom-catch= 0.64, θrandom-catch=.62). Taxonomic-level analysis confirmed these findings.ConclusionsRandom-catch and clean-catch urine samples showed substantial agreement on bacterial composition to paired mid-vaginal samples, indicating that the genitourinary microbiota may be a reliable proxy for assessing the overall composition of the vaginal microbiota via community state types. This data suggests that urine samples can, with proper interpretation, be utilized as a surrogate for developing preliminary data and hypothesis-generating studies.

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“…Out of the 17 eligible studies, seven originated from North-America 4 , 5 , 32 – 36 , three from Europe 37 – 39 , two from South-America 40 , 41 , three from Asia 42 – 44 and two from Africa 45 , 46 . Microbiome samples were taken before the third trimester in all studies.…”

Section: Resultsmentioning

confidence: 99%

“…Preterm birth was defined as birth before 37 completed weeks of gestation for all studies except one, where it was defined as before 34 weeks of gestation 4 . In twelve studies, a healthcare professional took the samples 4 , 5 , 32 , 37 – 39 , 41 – 46 , while the other five had self-sampling 33 – 36 , 40 . Furthermore, all studies except for two reported that the onset of preterm birth was spontaneous (Supplementary Table S4 ) 45 , 46 .…”

Section: Resultsmentioning

confidence: 99%

The vaginal microbiome and the risk of preterm birth: a systematic review and network meta-analysis

Guðnadóttir

Debelius

et al. 2022

Sci Rep

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Preterm birth is a major cause of neonatal morbidity and mortality worldwide. Increasing evidence links the vaginal microbiome to the risk of spontaneous preterm labour that leads to preterm birth. The aim of this systematic review and network meta-analysis was to investigate the association between the vaginal microbiome, defined as community state types (CSTs, i.e. dominance of specific lactobacilli spp, or not (low-lactobacilli)), and the risk of preterm birth. Systematic review using PubMed, Web of Science, Embase and Cochrane library was performed. Longitudinal studies using culture-independent methods categorizing the vaginal microbiome in at least three different CSTs to assess the risk of preterm birth were included. A (network) meta-analysis was conducted, presenting pooled odds ratios (OR) and 95% confidence intervals (CI); and weighted proportions and 95% CI. All 17 studies were published between 2014 and 2021 and included 38–539 pregnancies and 8–107 preterm births. Women presenting with “low-lactobacilli” vaginal microbiome were at increased risk (OR 1.69, 95% CI 1.15–2.49) for delivering preterm compared to Lactobacillus crispatus dominant women. Our network meta-analysis supports the microbiome being predictive of preterm birth, where low abundance of lactobacilli is associated with the highest risk, and L. crispatus dominance the lowest.

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An exploratory study of associations with spontaneous preterm birth in primigravid pregnant women with a normal cervical length

Cited by 6 publications

References 27 publications

Contribution of Lactobacillus iners to Vaginal Health and Diseases: A Systematic Review

Contribution of Lactobacillus iners to Vaginal Health and Diseases: A Systematic Review

Assessing the Concordance Between Urogenital and Vaginal Microbiota: Can Urine Specimens Be Used as a Proxy for Vaginal Samples?

The vaginal microbiome and the risk of preterm birth: a systematic review and network meta-analysis

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