Maternal and Fetal Outcomes Associated with Interleukin-17 Inhibitor Exposure During Pregnancy in Patients with Seronegative Arthritis: A Case Series of Nine

Objectives Interleukin-17 (IL-17) inhibitors, such as ixekizumab and secukinumab, are increasingly used in the treatment of seronegative inflammatory arthritis, including psoriatic arthritis and axial spondyloarthritis. However, data on their safety and outcomes during pregnancy remain limited. Given the expanding use of IL-17 inhibitors in individuals of reproductive age, further characterization of maternal and fetal outcomes is needed to inform clinical decision-making. Methods Nine pregnant individuals with seronegative inflammatory arthritis who were treated with IL-17 inhibitors were identified through the Pregnancy and Rheumatic Diseases Clinics at 2 Canadian centers. Clinical data were prospectively extracted by a trained research assistant using REDCap, electronic medical records, and relevant consult notes. Outcomes of interest included maternal disease activity during pregnancy, pregnancy complications, neonatal outcomes, and the presence of congenital anomalies. Results These patients were managed throughout all trimesters of pregnancy and followed for 6 weeks postpartum. The mean maternal age at conception was 34 years. Patient characteristics are summarized in Table 1. Pregnancy complications included gestational diabetes, preeclampsia, chorioamnionitis, gestational hypertension, and COVID-19 infection. Ankyloglossia was noted in 1 infant (P5). Neonatal complications included jaundice not requiring intervention (P4) and transient hypoglycemia and transaminitis (P7) (Table 1). Table 1. Patient characteristics including: maternal age at conception, diagnosis, gravidity, current biologic therapy, gestational age (GA) at delivery, mode of delivery, fetal birth weight, congenital malformations Conclusion In this prospective case series, IL-17 inhibitor exposure during pregnancy was not associated with an increased risk of major congenital anomalies or serious adverse neonatal outcomes. Although encouraging, these results are preliminary and do not establish safety. Confirmation in larger, controlled cohorts is needed. Larger, multicenter studies are needed to confirm these observations and better inform clinical guidance.