I did find some case reports in 2016 and 2017 of omalizumab being used in pregnant women with chronic spontaneous urticaria. No untoward sequelae were reported in the mothers or infants. Omalizumab is not approved for use in pregnant women but it was assigned to pregnancy category B by the FDA after Namazy et al published "The Xolair Pregnancy Registry (EXPECT): The safety of omalizumab use during pregnancy" (J Allergy Clin Immunol 2015;135:407-12). This was a prospective, observational study of pregnant women exposed to at least 1 dose of omalizumab within 8 weeks prior to conception or at any time during pregnancy. They looked at the following outcomes: rates of live births, elective terminations, stillbirths and congenital anomalies up to 18 months after delivery. They enrolled 191 woman, nearly 2/3 were enrolled during the first trimester. Of the 169 pregnancies with known outcomes, there were 156 live births of 160 infants, 1 fetal death/stillbirth, 11 spontaneous abortions and 1 elective termination. 22 (14.5%) of the 152 singleton births were premature and 16 (10.9%) of 147 with weight data were small for gestational age. 20 infants had congenital anomalies, 7 (4.4%) of whom had 1 major defect. There are tables which provide lists of the specific anomalies in the paper. Ankyloglossia was the most common birth defect, occurring in 6 infants. There was no observed pattern of anomalies. The authors concluded that the observations in the registry were not inconsistent with findings from other studies and that there was no apparent increase prevalence of major anomalies. There were no maternal deaths.
The published consensus is that it is not recommended to start omalizumab in pregnant women. However, if a woman becomes pregnant while receiving omalizumab and the benefits outweigh the risks, then therapy does not need to be discontinued.
I hope this information is of help to you.
Jacqueline A. Pongracic, MD, FAAAAI