Mum’s infection during pregnancy may raise newborn’s risk of IBD

Exposure to any infection during early pregnancy or to a gastrointestinal infection during late pregnancy contributes to the increased likelihood of inflammatory bowel disease (IBD) development, especially Crohn’s disease, in the offspring, according to a study.

Analyses of data from two Scandinavian birth cohorts showed a significantly higher risk of IBD in children born to mothers exposed to any infection at the early stage of pregnancy than in those born to mothers who did not have such an exposure (pooled adjusted hazard ratio [HR], 1.26, 95 percent confidence interval [CI], 1.02–1.55), reported one of the study authors Dr Tereza Lerchova of University of Gothenburg, Gothenburg, Sweden. [Guo A, et al, ESPGHAN 2024]

The association, Lerchova added, was driven by an excess risk of Crohn’s disease (pooled adjusted HR, 1.40, 95 percent CI,1.01–1.93).

A heightened Crohn’s disease risk was also seen for children born to mothers exposed to a gastrointestinal infection late in the pregnancy (pooled adjusted HR, 1.95, 95 percent CI, 1.34–2.84).

When infections were analysed without considering when they occurred during pregnancy, the link between maternal infection and childhood IBD disappeared, Lerchova noted. There was no increase in the risk of IBD among children born to mothers exposed to any (pooled adjusted HR, 0.99, 95 percent CI, 0.73–1.33), gastrointestinal (pooled adjusted HR, 0.96, 95 percent CI, 0.47–1.96), or respiratory infections (pooled adjusted HR, 1.00, 95 percent CI, 0.81–1.23) at any time during the pregnancy relative to children whose mothers had no such exposure.

Finally, prenatal antibiotic exposure showed no association with the outcome (pooled adjusted HR, 1.15, 95 percent CI, 0.93–1.44).

These findings provide evidence that “maternal infection … during pregnancy may imprint on the developing foetal immune system and influence the offspring's susceptibility to immune-mediated diseases,” according to Lerchova.

For the study, Lerchova and colleagues followed participants from the Swedish ABIS (n=16,223) and Norwegian MoBa (n=101,270) cohorts. A total of 451 IBD cases were documented over 2,024,299 person-years of follow-up. IBD diagnosis was defined by ≥2 records in national registers. Data on maternal infections and antibiotic treatment during pregnancy were obtained using questionnaires.

“To the best of our knowledge, we were one of the first to prospectively assess prenatal exposure to infections and antibiotics and later risk of IBD,” Lerchova said, adding that their analysis leveraged a large-scale, population-based national cohort dataset, which provided a follow-up period exceeding 15 years.

The main limitation of the study, on the other hand, was the self-reported nature of the data on maternal infections and antibiotic use.