NEW YORK (Reuters Health)—Babies born to mothers who took anti-tumor necrosis factor (anti-TNF) agents during pregnancy have detectable drug in their bodies up to 12 months of age, new findings show.
These infants should therefore not receive live vaccines during their first year of life, Dr. Mette Julsgaard of Aarhus University Hospital in Denmark and her colleagues conclude in a report online April 7 in Gastroenterology.
Many women with inflammatory bowel disease (IBD) require treatment with anti-TNF drugs during pregnancy, Dr. Julsgaard and her team note. They add that although studies have so far not linked in-utero exposure to adverse neonatal outcomes, there is little data on how infants clear the drug and whether exposure may affect childhood development.
To investigate, the researchers looked at 80 mother-baby pairs from Denmark, Australia and New Zealand. Thirty-six of the mothers received adalimumab during pregnancy, 44 infliximab and 39 also received thiopurines.
Median duration of anti-TNF treatment was 2.5 years. Women on adalimumab received their last pregnancy dose at median gestational week (GW) 35, while the last dose of infliximab was given at median GW 30. Thirty-eight women had a disease relapse while pregnant, while 42 remained in remission.
Cord blood concentrations of anti-TNF agents were higher than maternal concentrations, with a median ratio of infant to maternal concentration at birth of 1.21 for adalimumab and 1.97 for infliximab. Both maternal and cord blood concentrations were inversely correlated with duration since last exposure.
Eight of the babies exposed to adalimumab (22%) had no detectable level of the drug in their cord blood, while infliximab was detected at birth in all of the exposed infants. Mean time to clearance was four months with adalimumab and 7.3 months with infliximab. One infant had detectable levels of infliximab at 12 months, which were cleared by age 15 months.
Four infants developed bacterial infections during their first year, while 16 had viral infections, all of which had benign courses. The relative risk of any infection was 2.7 for infants born to mothers who received both an anti-TNF agent and thiopurine, compared with those on anti-TNF monotherapy.
“It is reassuring that all infant infections had a benign course. Still, combination therapy in pregnant women should be carefully counterbalanced between risk of disease activity in pregnancy (if thiopurine is discontinued) and thereby increased risk of adverse pregnancy outcome such as preterm birth and small for gestational age, and an increased risk of infection in the offspring if combination therapy is continued,” Dr. Julsgaard tells Reuters Health via e-mail. “Therefore pregnant women on combination therapy should receive thorough counseling.”