A University of Gothenburg study shows that inflammatory bowel disease is a risk factor for preterm birth even when in apparent disease remission.
The findings of the study may affect recommendations for women with ulcerative colitis who are trying to conceive.
The study has been published in the journal eClinicalMedicine.
What is inflammatory bowel disease?
Inflammatory bowel disease is a chronic inflammatory disease affecting approximately 0.5% of the world’s population. Inflammatory bowel disease includes ulcerative colitis and Crohn’s disease. Unlike irritable bowel syndrome, Inflammatory bowel disease can cause visible damage to the mucous membrane that lines the intestines.
Symptoms of the disease tend to reoccur and flare up before periods of low or no disease activity. The disease usually appears between the ages of 15-30, therefore its impact on pregnant women is particularly prevalent.
The disease has previously been linked to negative birth outcomes, including preterm birth. These effects are most common in women showing signs of active disease. As well as this, women without obvious disease activity can have microscopic inflammation in the intestinal mucosa, it has been unknown whether this microscopic inflammation is associated with risks in pregnancy.
The University of Gothenburg study found that microscopic inflammation in inflammatory bowel disease, especially ulcerative colitis, is linked to a heightened risk of giving birth prematurely.
Researchers find a clear association with preterm risk
In babies born to women with microscopic inflammation due to the disease, 9.6% were born prematurely and 6.5% of children were born preterm to women without microscopic inflammation from inflammatory bowel disease. This represents a relative risk increase of 46%. Microscopic inflammation was not associated with any other adverse pregnancy outcomes, such as growth restriction.
The findings were based on registered data on women in Sweden, diagnosed with inflammatory bowel disease between 1990–2016. The study examined 1,223 children of women with microscopic bowel inflammation of the intestine and 630 children of women with the disease who had healed intestinal mucosa.
The researchers also retrieved data from several national health registers, such as the Swedish Medical Birth Register and the Swedish Quality Register for Inflammatory Bowel Disease (SWIBREG).
“Our results suggest that IBD treatment aimed at not merely alleviating symptoms of IBD, but also microscopically healing the intestine, which can reduce the risk of giving birth preterm. If our results hold up in future studies, they may therefore be the basis for recommendations to confirm microscopic healing before pregnancy, to reduce such risks,” said Karl Mårild, the study’s first author and corresponding author. Mårild, is also an associate professor of paediatrics at Sahlgrenska Academy, University of Gothenburg.
“Even a modestly increased relative risk of preterm birth is important, given that preterm birth can greatly affect the child’s health in both the short and the long term. Preterm birth is still one of the most common causes of death for children under the age of five in Sweden,” concluded Mårild.