Pregnant Women with IBD Have Increased Vaginal Inflammation

Healthy vaginal microbiomes and pregnancies are typically characterized by low microbial diversity, often dominated by Lactobacillus species.¹ For individuals with inflammatory bowel disease (IBD), pregnancy introduces heightened risks of preterm birth to an increased likelihood of bacterial vaginosis, a condition rooted in vaginal microbiota imbalance.

Despite the central role of the vaginal microbiome in both maternal and neonatal health, its composition in pregnant patients with IBD has remained largely unexplored. This motivated researchers at the University of Massachusetts Chan Medical School to compare the vaginal microbiome between pregnant women both with and without IBD.

Their findings, published in PLoS One, revealed that despite having similar vaginal microbiota, pregnant women with IBD had a more pro-inflammatory vaginal environment.² Notably, regardless of IBD status, patients with healthier diets also had lower levels of pro-inflammatory cytokines. Together, these findings suggest that the inflammatory environment may contribute to the increased risk of preterm birth in this demographic and that diet may aid in reducing inflammation.

In this study, the researchers recruited 48 individuals in their third trimester: 23 with diagnosed IBD and 25 healthy counterparts. They collected vaginal swabs, performed 16S ribosomal RNA sequencing, and examined the expression of cytokines associated with poor pregnancy outcomes.

Although the vaginal microbiota of pregnant individuals with IBD did not differ from the healthy control group, the cytokine profile varied. Those with IBD had higher levels of pro-inflammatory cytokines, such as interleukin (IL)-6, IL-8, and IL-17, and lower expression of immune-regulating and anti-inflammatory cytokines, including interferon gamma (IFN-γ) and IL-4. Compared to those without IBD, these results point to a more pro-inflammatory environment within the vaginal mucosa.

Next, because diet largely influences gut microbial diversity, the researchers sought to investigate if it also influenced vaginal microbial composition. Looking at dietary intake, the researchers found that, regardless of IBD status, a higher intake of vegetables or a lower intake of added sugars was associated with higher levels of the beneficial microbe Lactobacillus crispatus, lower levels of the pro-inflammatory IFN-γ, and increased levels of the anti-inflammatory IL-4. It is possible that diet may impart some effect on the vaginal microbiome, though further analysis is needed.

While the researchers acknowledged a small sample size as a limitation, these findings provide novel insights into the interplay between the vaginal microbiota, cytokine expression, and diet in pregnant individuals with and without IBD.