A pregnant woman's daily diet may have a subtle impact on the safety of her pregnancy. Sugar consumption is linked to inflammation in the vaginal environment, which is an important predictor of premature birth. 

The findings are from a study published in the open-access journal PLOS One recently, by researchers led by Dr Ana Maldonado-Contreras of the University of Massachusetts Chan Medical School in the United States. The study focuses on pregnant women with inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, but the findings apply to all expectant mothers.

Preterm birth, defined as delivery before 37 weeks of gestation, is still a primary cause of neonatal sickness and mortality globally. Women with IBD are already known to be at higher risk, even if their digestive symptoms appear to be controlled. 

"Our study indicates that clinical remission does not necessarily imply that the risk has vanished," stated Dr Maldonado-Contreras. "There is a persistent inflammatory signal in the vaginal tissue that may help explain why these pregnancies remain vulnerable." 

The study included 48 pregnant women in their third trimester, 23 with IBD and 25 without it. Moreover, over half of the IBD patients were in remission at the time of the study. Each participant gave vaginal swabs and performed three extensive, interviewer-led dietary assessments. 

While the types of bacteria in the vagina were largely comparable between the two groups, the immune response differed. Pregnant IBD patients had increased levels of pro-inflammatory cytokines—chemical messengers that signal inflammation—such as IL-6, IL-8, and IL-17. At the same time, they had reduced levels of cytokines, which help reduce inflammation. 

Inflammation in the vaginal canal is a documented indicator of premature birth. "It is like a silent alarm system," remarked one of the researchers. "You may not feel unwell, but the body is already under stress." 

Diet revealed as an important component. Across all individuals, those who ate more vegetables and drank less added sugar had greater levels of Lactobacillus crispatus, a beneficial bacterium that aids in vaginal health. These ladies also had decreased inflammatory signals and increased anti-inflammatory markers. 

This relationship is referred to as the "gut-vaginal axis" by scientists, which is a burgeoning field of study that investigates how food choices affect digestion and reproductive health. Simply put, what we consume can alter the microbes in our bodies, which influences inflammation. 

"What surprised us was how strongly diet tracked with inflammation, regardless of whether a woman had IBD," according to the authors. "This suggests diet is a modifiable risk factor." 

The study has limitations. The sample size was small, and all samples were taken during the third trimester, making it impossible to trace changes earlier in pregnancy or prove cause and effect. Nonetheless, the researchers feel the findings convey a useful lesson. 

Small dietary changes may benefit expecting mothers, particularly those with IBD. A diet high in veggies and low in added sugars may promote beneficial bacteria and reduce hidden inflammation, thus lowering the risk of preterm birth.