Natalizumab Use During the Third Trimester of Pregnancy | Congenital Defects | JAMA Neurology | JAMA Network
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Case Report/Case Series
July 2014

Natalizumab Use During the Third Trimester of Pregnancy

Author Affiliations
  • 1Department of Neurology, St Josef-Hospital, Ruhr University Bochum, Bochum, Germany
  • 2Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena
  • 3Department of General Pediatrics, University Children’s Hospital Münster, Münster, Germany
  • 4University Children’s Hospital Mannheim, Heidelberg University, Heidelberg, Germany
  • 5Neurologic Practice Hamburg, Hamburg, Germany
  • 6Neurologic Practice Barsinghausen, Barsinghausen, Germany
  • 7Department of Neurology, University of Bonn, Bonn, Germany
  • 8Faculty of Pharmacy, University of Dusseldorf, Dusseldorf, Germany
  • 9Department of Neurology, kbo-Isar-Amper-Klinikum München-Ost, Munich, Germany
  • 10Institute for Clinical Neuroimmunology, Ludwig-Maximilians-University, Munich, Germany
  • 11Biogen Idec, Cambridge, Massachusetts
JAMA Neurol. 2014;71(7):891-895. doi:10.1001/jamaneurol.2014.209

Importance  Natalizumab reduces multiple sclerosis relapses very effectively; however, severe disease activity may return once natalizumab treatment is withdrawn, as recommended during pregnancy. Sometimes restarting natalizumab treatment may be the best option for the mother, but the consequences for the infant are unknown. Except for a few single case reports, to our knowledge, comprehensive data about third-trimester natalizumab exposure are scant.

Observations  In a case series of 12 women with 13 pregnancies and highly active multiple sclerosis who were treated with natalizumab during their third trimester of pregnancy, we assessed the clinical and laboratory effects on the newborns. We observed mild to moderate hematologic alterations in 10 of 13 infants including thrombocytopenia and anemia. In a subsample of 5 mother-child pairs, we analyzed natalizumab levels in the umbilical cord blood. Natalizumab was detectable in all 5 newborns.

Conclusion and Relevance  Natalizumab can be a therapeutic option in patients with highly active multiple sclerosis during pregnancy. We recommend that a pediatrician be available at the time of delivery to evaluate for potential complications of anemia and thrombocytopenia in newborns exposed to natalizumab during the third trimester.