Pregnant individuals diagnosed with inflammatory bowel disease (IBD) show elevated levels of pro-inflammatory immune molecules, known as cytokines, in their vaginal mucosa compared to healthy pregnant individuals. This finding stems from a study led by Ana Maldonado-Contreras at the University of Massachusetts Chan Medical School and published in PLOS One. The research highlights the unique challenges faced by pregnant individuals with IBD, such as an increased risk of adverse pregnancy outcomes, including preterm birth.
The study involved 48 participants in their third trimester, comprising 23 individuals with IBD—specifically, 18 with Crohn’s disease and 5 with ulcerative colitis—and 25 healthy controls. Notably, over half of the participants with IBD were in remission at the time of the study. Participants provided vaginal swabs and underwent three nutrition assessments to evaluate their dietary intake.
Researchers discovered that, while the vaginal microbiota in pregnant individuals with IBD was similar to that of healthy participants, those with IBD exhibited higher levels of pro-inflammatory cytokines such as IL-6, IL-8, and IL-17. Conversely, they had lower levels of the immune-regulating cytokine IFN-γ and the anti-inflammatory cytokine IL-4. These findings suggest a persistent pro-inflammatory environment in the vaginal mucosa of pregnant individuals with IBD, even during remission.
The study also established a link between diet and inflammation. Across all participants, a higher intake of vegetables and reduced consumption of added sugars correlated with increased levels of the beneficial microbe Lactobacillus crispatus and decreased levels of the pro-inflammatory cytokine IFN-γ. Additionally, higher vegetable intake was associated with elevated levels of the anti-inflammatory IL-4.
Despite the insights gained, the study acknowledges limitations, including its modest sample size and the restriction of data collection to the third trimester. These factors hinder the ability to assess changes in the vaginal environment throughout pregnancy or draw definitive conclusions regarding causation. Nevertheless, the authors emphasize the importance of these findings in understanding the heightened risks faced by pregnant individuals with IBD.
The research provides valuable information that could influence dietary recommendations and management strategies for pregnant individuals with IBD, aiming to mitigate inflammatory responses that may contribute to poor pregnancy outcomes. The full study, titled “Association of vaginal IL-4, IL-6, IL-8, IL-17, IFN-γ, and dietary intake with IBD status and vaginal microbiota in pregnant individuals,” will be available in PLOS One in March 2026 (DOI: 10.1371/journal.pone.0335178).