Pregnancy and infant outcomes following abatacept exposure during pregnancy

Abatacept is approved for the treatment of moderate-severe RA, JIA and PsA in the USA and elsewhere. The purpose of this study was to estimate the incidence/birth prevalence of selected maternal and infant outcomes in pregnancies exposed to abatacept.

Pregnant women exposed to any dose of abatacept from the first day of the last menstrual period to the end of the first trimester who resided in the USA or Canada were enrolled in the Organization of Teratology Information Specialists Abatacept Pregnancy Exposure Registry between 2007 and 2019. Data on exposures, outcomes and covariates were collected by maternal interviews, medical records and study-related physical examinations up to 1 year postpartum.

The sample consisted of 30 abatacept-exposed pregnancies. Sixteen were enrolled prospectively and were treated for RA or PsA; 14 did not meet the prospective criteria and were enrolled in an exposure series. Of those prospectively enrolled, 2/13 (15.4%) involved an infant with a major birth defect, 2/16 (12.5%) ended in spontaneous abortion and 2/13 (15.4%) delivered preterm. In the exposure series, 5/14 livebirths (35.7%) ended with an infant with a major birth defect, 2 of which were chromosomal or genetic, and 6/14 (42.9%) delivered preterm.

There were no patterns of major or minor birth defects identified in either group. In the exposure series, selected adverse outcomes were more frequent, likely due to biases that led to exclusion of these pregnancies from the prospective cohort.