Pregnancy's Stronghold on the Vaginal Microbiome

Abstract

ObjectiveTo assess the vaginal microbiome throughout full-term uncomplicated pregnancy.MethodsVaginal swabs were obtained from twelve pregnant women at 8-week intervals throughout their uncomplicated pregnancies. Patients with symptoms of vaginal infection or with recent antibiotic use were excluded. Swabs were obtained from the posterior fornix and cervix at 8–12, 17–21, 27–31, and 36–38 weeks of gestation. The microbial community was profiled using hypervariable tag sequencing of the V3–V5 region of the 16S rRNA gene, producing approximately 8 million reads on the Illumina MiSeq.ResultsSamples were dominated by a single genus, Lactobacillus, and exhibited low species diversity. For a majority of the patients (n = 8), the vaginal microbiome was dominated by Lactobacillus crispatus throughout pregnancy. Two patients showed Lactobacillus iners dominance during the course of pregnancy, and two showed a shift between the first and second trimester from L. crispatus to L. iners dominance. In all of the samples only these two species were identified, and were found at an abundance of higher than 1% in this study. Comparative analyses also showed that the vaginal microbiome during pregnancy is characterized by a marked dominance of Lactobacillus species in both Caucasian and African-American subjects. In addition, our Caucasian subject population clustered by trimester and progressed towards a common attractor while African-American women clustered by subject instead and did not progress towards a common attractor.ConclusionOur analyses indicate normal pregnancy is characterized by a microbiome that has low diversity and high stability. While Lactobacillus species strongly dominate the vaginal environment during pregnancy across the two studied ethnicities, observed differences between the longitudinal dynamics of the analyzed populations may contribute to divergent risk for pregnancy complications. This helps establish a baseline for investigating the role of the microbiome in complications of pregnancy such as preterm labor and preterm delivery.

Impact of maternal nutrition in pregnancy and lactation on offspring gut microbial composition and function

“…47 Subsequently, 2 independent studies further examined the vaginal microbiome longitudinally during pregnancy through self-collection methods. 48,49 These studies were in agreement with Aagaard et al and demonstrated that a diversity decreased and Lactobacillus species increased with increasing gestational age. 48,49 Altogether, alterations in vaginal microbiota are associated with pregnancy with an increased abundance in Lactobacillus species.…”

“…48,49 These studies were in agreement with Aagaard et al and demonstrated that a diversity decreased and Lactobacillus species increased with increasing gestational age. 48,49 Altogether, alterations in vaginal microbiota are associated with pregnancy with an increased abundance in Lactobacillus species. This may be a mechanism to increase lactic acid production in the vaginal cavity to protect the fetus from infection.…”

The Intestinal Microbiota Influences Campylobacter jejuni Colonization and Extraintestinal Dissemination in Mice

“…Genomic DNA extraction was performed using a MoBio UltraClean soil DNA isolation kit (MoBio Laboratories, Inc., Carlsbad, CA) and an MP FastPrep instrument (MP Biomedicals, Solon, OH) set at 40 s for rapid cell lysis. Each of the individually extracted DNA samples was quantified using a high-sensitivity Qubit kit (Life Technologies), and 15 ng of DNA was PCR amplified using specific bar-coded primers around the V3-V5 16S rRNA, as described previously (24). Amplified samples were sequenced using a 16S rRNA high-throughput next-generation Illumina MiSeq (Illumina, San Diego, CA) sequencing platform.…”

Normal flora and bacterial vaginosis in pregnancy: an overview

“…The decreased diversity and richness of the vaginal microbiota in pregnancy are supported by Walther-António et al (2014) who studied the vaginal microbiome of pregnant Caucasian women. The authors reported that L. crispatus and L. iners are the two species that dominated the microbial content of the women studied throughout the course of pregnancy.…”

“…It is reported that the vaginal bacterial community structure between pregnant women may be more stable than the community structure between non-pregnant women (Romero et al, 2014;Walther-António et al, 2014). Romero and colleagues (2014) suggested that during pregnancy, vaginal microbial communities dominated by Lactobacillus species do shift from one CST to another CST, dominated by another Lactobacillus species, but rarely to a CST dominated by anaerobic bacteria.…”