Montreal—Some guidelines, including those from the European League Against Rheumatism, recommend discontinuing infliximab and adalimumab before 20 weeks of gestation and etanercept before 31 to 32 weeks to minimize the risk of infections in offspring of expectant mothers with rheumatoid arthritis (RA).

A new study published in Arthritis & Rheumatology suggests, however, that those recommendations might need to be reconsidered.

McGill University–led research indicates that when pregnant women take certain RA drugs that may cause immunosuppression, their children do not have a significant excess risk of developing serious infections.

Concerns have focused on tumor necrosis factor inhibitors (TNFis), which are transported across the placenta, and their ability to cause immunosuppression and compromise infants’ ability to fight infections. Data on whether that actually has happened remains limited, study authors point out.

To investigate, the researchers used U.S. insurance claims data from 2011 to 2015 to identify 2,989 offspring of women with RA and a randomly selected group of 14,596 control children. Overall, 12.7% of the pregnant RA patients were exposed to TNFis, exposure defined as at least one filled prescription during pregnancy.

Researchers followed the offspring from birth until 12 months of age, until the first indication of serious infection, end of commercial insurance eligibility, death, or end of study period (December 30, 2015), whichever came first.

Results indicate that the percentage of serious infections in those with no TNFi exposure was similar (2.0%) to control offspring (1.9%), while the percentage of serious infections in offspring with TNFi exposure was 3.2%.

Even after adjusting for maternal demographics, comorbidities, pregnancy complications, and medications, researchers say they were unable to establish an increased risk of serious infections in offspring exposed to TNFis versus both control offspring and offspring of mothers with RA who did not use TNFis.

“Our study provides new evidence to counsel RA women contemplating pregnancy,” explained Évelyne Vinet MD, PhD, of the Research Institute of the McGill University Health Centre.

“Within the largest cohort of RA offspring exposed to TNFis ever assembled, we did not observe a marked excess risk for serious infections versus unexposed RA offspring and children from the general population. Our data are potentially reassuring; however, we could not exclude a differential risk according to specific TNFi characteristics, with infliximab potentially resulting in a 3-fold increase in the risk of serious infections compared with other TNFis.”

While urging future studies, Vinet also recommended that clinicians continue to follow current recommendations when treating RA patients during pregnancy.

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