Safety of infliximab use during pregnancy.

Infliximab is a chimeric IgG1 monoclonal antibody to tumor necrosis factor alpha (TNF)-α used in the treatment of inflammatory bowel disease and rheumatoid arthritis. Infliximab does not actively cross the placenta during the first trimester, but undergoes efficient placental transfer during the late second and third trimesters and is detectable in the infant's serum for several months after birth. This raises concerns about immunological risks of infection and response to vaccines. Available evidence from registry studies and case reports involving more than 300 pregnancy outcomes suggest that infliximab carries low fetal risk and is compatible with use during conception and the first two trimesters of pregnancy. The long-term effects of infliximab exposure on the developing immune system are yet unknown. Based on limited data from several case reports, infants born with detectable levels of infliximab do not seem to have an increased risk of infections in their first year of life and have normal responses to nonlive vaccines. However, a fatal case of disseminated mycobacterial infection has been reported in an infant who received BCG vaccine at 3 months of age, to a mother who had been treated with infliximab throughout her pregnancy. Vaccination with live viruses should be postponed in infants exposed to infliximab in utero, until serum levels are undetectable which may require more than 6 months. Discontinuing infliximab early in the third trimester should be considered in order to minimize late fetal exposure.