Pregnancy outcomes after maternal exposure to rituximab

Rituximab is a chimeric anti-CD20 monoclonal B cell-depleting antibody indicated for certain hematologic malignancies and active rheumatoid arthritis with inadequate response to tumor necrosis factor antagonists. Despite counseling to avoid pregnancy, women may inadvertently become pregnant during or after rituximab treatment. Using the rituximab global drug safety database, we identified 231 pregnancies associated with maternal rituximab exposure. Maternal indications included lymphoma, autoimmune cytopenias, and other autoimmune diseases. Most cases were confounded by concomitant use of potentially teratogenic medications and severe underlying disease. Of 153 pregnancies with known outcomes, 90 resulted in live births. Twenty-two infants were born prematurely; with one neonatal death at 6 weeks. Eleven neonates had hematologic abnormalities; none had corresponding infections. Four neonatal infections were reported (fever, bronchiolitis, cytomegalovirus hepatitis, and chorioamnionitis). Two congenital malformations were identified: clubfoot in one twin, and cardiac malformation in a singleton birth. One maternal death from pre-existing autoimmune thrombocytopenia occurred. Although few congenital malformations or neonatal infections were seen among exposed neonates, women should continue to be counseled to avoid pregnancy for ≤ 12 months after rituximab exposure; however, inadvertent pregnancy does occasionally occur. Practitioners are encouraged to report complete information to regulatory authorities for all pregnancies with suspected or known exposure to rituximab.