Therapeutic infliximab drug level in a child born to a woman with ulcerative colitis treated until gestation week 31

A 26 year old woman with ulcerative colitis was treated with regular infliximab (IFX) infusions until gestation week 31, and gave birth to a healthy child at gestation week 37. Maternal IFX trough level was relatively high during the course of pregnancy. In the infant, therapeutic level of IFX was detectable at week 16 after birth, but not at reassessment at week 28. Anti-IFX antibodies were consistently below the detection limit in the patient and in the child. This case illustrates that IFX is transferred through the placenta to the embryo, and may result in therapeutic drug levels in the newborn child despite IFX discontinuation in third trimester 6 weeks prior to delivery. The half life of IFX appeared markedly longer in infants as compared to adults. The safety of IFX beyond the first trimester is unknown, and this case highlights the need for further investigations of maternal transfer of IFX as well as the risks associated with IFX administrations in the second and third trimester.