The widespread use of anti-TNF therapy for inflammatory bowel disease has improved clinical outcomes including fewer surgeries, hospitalizations, and complications. One consequence of this usage has been the exposure of infants to biologics due to their usage by their mothers during pregnancy. A recent study (M Julsgaard et al. Gastroenterol 2016; 151: 110-19) explores this topic further.
In this study, the authors prospectively followed 80 pregnant women: 36 received adalimumab & 44 infliximab. In addition, 39 received concomitant thiopurine therapy.
- The time from last exposure to anti-TNF agent correlated inversely with the concentration of these drugs in the umbilical cord and in mothers at the time of birth.
- Median ratio for infant: mother drug concentration at birth was 1.21 for adalimumab and 1.97 for infliximab.
- Mean time for drug clearance: 4.0 months for adalimumab and 7.3 months for infliximab. Drugs were not detected after 9 months of life for adalimumab and after 12 months of life for infliximab.
- No increased risk of adverse pregnancy outcomes were identified; preterm birth was low (n=3 or 3.8%). 48% of women experienced a disease relapse during pregnancy.
- In this small study, the relative risk for infection was 2.7 in infants exposed to combination therapy. Benign courses of viral infections were noted in 16 (20%) of the entire cohort and of bacterial infections in 4 (5%).
The authors recommend avoidance of live virus vaccines in biologically-exposed infants for up to 1 year unless drug clearance has been documented. Currently, this would affect only rotavirus vaccination.
My take (borrowed from editorial pgs 25-26): “For now, the sum of evidence seems to support continued use of anti-TNF therapy in pregnancy when clinically indicated and, despite measureable levels in offspring, there does not seem to be a significant clinical consequence.”
Related study: “Adverse Pregnancy Outcomes among women with inflammatory bowel disease: a population-basd study from England” Inflamm Bowel Dis 2016; 22: 1621-30. The authors identified 1969 pregnancies from a total of 364,363 singleton pregnancies. Women with Crohn’s had increased preterm births with an Odd ratio of 1.42, babies with low birth weight (OR 1.39); women with ulcerative colitis had only a small increase risk in preterm birth (absolute risk <2.7%).
Related blog posts: