It is unknown if Xolair can safely be taken during pregnancy and the manufacturer of Xolair makes no recommendations regarding taking Xolair during pregnancy. Before prescribing Xolair during pregnancy, a doctor must weigh up the risks to the fetus, the risks to the mother of uncontrolled asthma, and the benefits of taking Xolair.

The following has been documented:

• Animal studies using up to 10 times the maximum recommended human dose have failed to reveal evidence of harm to the fetus from Xolair
• Xolair binds to IgE and human IgG does cross the placenta which means fetal exposure to this drug is possible. The potential for harm to the fetus is unknown.
• Uncontrolled asthma in pregnancy is associated with preeclampsia, prematurity, low birth weight, and small for gestational age
• A pregnancy registry that tracked women taking Xolair during pregnancy showed no increase in major birth defects or miscarriage. Babies born to women taking Xolair during pregnancy were more likely to have a lower birth weight than those born to other groups of women, despite the gestational age being similar, and it is unclear whether this was due to Xolair or due to disease severity, since women taking Xolair were more likely to have severe asthma.

When comparing babies born to women taking Xolair during pregnancy for asthma to those born to women with asthma who were not taking Xolair:
• Major congenital defect rates were similar (8.1% Xolair, 8.9% comparator)
• Number of live births were similar (91.1% Xolair, 99.3% comparator)
• Low birth weights were more common in the Xolair group (13.7% Xolair, 9.8% comparator).