The Study
The prospective cohort study is a substudy of a larger 2023 one that included biologic use in a range of maternal illnesses, not just IBD.
For the current study, Seow and colleagues identified 57 infants born to 52 mothers with IBD attending a pregnancy clinic at the University of Calgary in the period 2019-2023. Almost 81% of the mothers had Crohn’s disease, and the median duration of IBD was 10 years. The median gestational age at delivery was 39 weeks, and almost 60% of deliveries were vaginal. The infants had been exposed in utero to infliximab (n = 21), adalimumab (n = 19), vedolizumab (n = 10), and ustekinumab (n = 7) in the third trimester.
The 57 biologic-exposed infants underwent standardized clinical assessments, drug concentration, and immune function testing. The live oral rotavirus vaccine series was provided to 50 infants, with the first dose at a median of 13 weeks of age. Immunologic assessments validated for age were normal in all infants despite median infliximab concentrations of 6.1 μg/mL (range, 0.4-28.8 μg/mL), adalimumab concentrations of 1.7 μg/mL (range, 0.7-7.9 μg/mL), ustekinumab concentrations of 0.6 μg/mL (range, 0-1.1), and undetectable for vedolizumab at 10.7 weeks of age.
As anticipated, infant immune function was normal regardless of circulating drug levels.
The overall message, said Seow, is “healthy mum equals healthy baby. Be more concerned regarding active inflammation than active medications. In almost all circumstances, treat to target in pregnancy as you would in the nonpregnant state.” She added, however, that further studies are needed to determine the safety and optimal timing of other live vaccines, such as the BCG, in the presence of biologic therapy.
This study was funded by the Alberta Children’s Hospital Research Institute. Seow reported advisory/speaker’s fees for Janssen, AbbVie, Takeda, Pfizer, Fresenius Kabi, Bristol-Myers Squibb, Pharmascience, and Lilly, as well as funding from Alberta Children’s Hospital Research Institute, Crohn’s and Colitis Canada, the Canadian Institutes of Health Research, and Calgary Health Trust, and data safety monitoring from New South Wales Government Health, Australia. Multiple coauthors disclosed similar consulting or speaker relationships with private industry. Spencer had no competing interests with regard to her comments.
A version of this article first appeared on Medscape.com.