Pregnancy outcome after tocilizumab therapy in early pregnancy-a case series from the German Embryotox Pharmacovigilance Center

•TCZ does not seem to pose a major teratogenic risk, but experience is still too limited for a well-grounded risk assessment.•Larger studies are needed to ascertain safety of TCZ during pregnancy before its use can be recommended.•In case of inadvertent TCZ treatment in early pregnancy a detailed prenatal ultrasound should be offered and the patient reassured.

Tocilizumab (TCZ) is not recommended for use during pregnancy due to limited data, but pregnancies nevertheless occur and pregnant women need to be counseled about potential fetal risks. Participants of this study were recruited from the pool of callers who spontaneously contact the pharmacovigilance center “Embryotox” Berlin for risk assessment during pregnancy. Of 22 identified cases with TCZ exposure during pregnancy, 16 prospectively enrolled cases with maternal and two cases with paternal TCZ therapy could be completed. The outcomes of the 16 maternal cases were: four spontaneous abortions (SAB), one induced abortion for personal reasons and 11 live-born infants. Congenital malformations were not recorded, but one SAB at week 15 + 3 days was complicated by hydrops fetalis of unknown origin. An incidental continuation of TCZ into early pregnancy does not justify an elective termination. However, a detailed prenatal ultrasound should be offered.