Birth outcomes in women who have taken vedolizumab in pregnancy: results from the Vedolizumab Pregnancy Exposure Registry

There are limited data on the safety of vedolizumab in pregnancy for the treatment of Crohn’s disease or ulcerative colitis. Between 2015 and 2022, the Organization of Teratology Information Specialists (OTIS) conducted a prospective, observational pregnancy registry study with 275 pregnant women residing in the U.S. or Canada. Women were enrolled in one of three cohorts: vedolizumab-exposed (N=99); disease-matched unexposed to vedolizumab, but treated with another biologic in pregnancy (N=76); or unexposed with no chronic health conditions (N=100). Women and their infants were followed up to one year postpartum with maternal interviews, questionnaires, medical records abstraction, and a subset of infants who received a physical examination. Study outcomes were major structural birth defects, minor birth defects, pregnancy loss, preterm delivery, pre- and post-natal growth deficiency, serious or opportunistic infections, malignancies, and developmental milestones. In the overall registry, 17/275 (6.2%) of pregnancies were lost-to-follow-up. Among pregnancies ending in at least one liveborn infant, 7/94 (7.4%) in the vedolizumab-exposed cohort compared to 4/71 (5.6%) in the disease-matched cohort had a major birth defect (adjusted risk ratio [aRR] 1.07, 95% Confidence Interval [CI] 0.33, 3.52). Compared to the disease-matched cohort, women in the vedolizumab-exposed group were not statistically significantly more likely to experience spontaneous abortion (adjusted hazard ratio [aHR] 1.01, 95% CI 0.17, 5.89). Women in the vedolizumab-exposed group were slightly but not significantly more likely to deliver preterm (aHR 1.58, 95% CI 0.65, 3.82). No significant increased risks were noted with vedolizumab exposure for any of the other study outcomes. These data add reassuring evidence in support of the safety of vedolizumab in pregnancy.