The manufacturer makes no recommendation regarding use during pregnancy.

AU TGA pregnancy category: B1
US FDA pregnancy category: Not assigned

Comments:
-An omalizumab pregnancy registry showed no increase in major birth defects or miscarriage; the low birth weight risk increased compared to other cohorts (despite average gestational age), but the omalizumab patients had more severe asthma than the other cohorts, making it unclear if the drug or disease severity affected birth weight.
-Human IgG crosses the placenta; fetal exposure to this drug is possible.
-Uncontrolled asthma in pregnancy is associated with risks including preeclampsia, prematurity, low birth weight, and small for gestational age.
-Closely monitor and optimize asthma control during pregnancy.

Animal studies have failed to reveal evidence of fetal harm in doses up to 10 times the maximum recommended human dose.

This drug crosses the placental barrier and the potential for harm to the fetus is unknown.

The background birth defect and miscarriage risk for the indicated population is not known. In the US general population, the estimated major birth defect risk is 2 to 4% and the miscarriage risk is 15 to 20%.

A prospective US pregnancy registry (2006 to 2018) had 246 mother-child pairs that had first trimester omalizumab exposure and 250 any time pregnancy exposures (median exposure duration 8.7 months) that were compared to disease matched external cohorts; major congenital defect rates were similar (8.1% omalizumab, 8.9% comparator), as were live births (91.1% omalizumab, 99.3% comparator); low birth weight was more common (13.7% omalizumab, 9.8% comparator), however the omalizumab group had more severe asthma, making it unclear if the drug or disease severity affected birth weight.

AU TGA pregnancy category B1: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have not shown evidence of an increased occurrence of fetal damage.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

See references

-Animals administered 75 mg/kg/week of subcutaneous omalizumab showed limited drug in the milk.

Caution is recommended.

Excreted into human milk: Unknown
Excreted into animal milk: Yes

Comments:
-There is no information regarding this drug on the presence in human milk, the effects on a breastfed infant, or effects on milk production.
-Immunoglobulin (IgG) is present in small amounts in human milk; this drug is a human monoclonal antibody (IgG1 kappa).
-In an omalizumab pregnancy registry, 186 infants out of 230 were breastfed; infants exposed through breastmilk did not show increased infections and infestation compared to non-exposed infants.
-Consider the developmental and health benefits of breastfeeding along with the mother's clinical need for this medication as well as any potential adverse effects from this drug or the underlying maternal condition.

See references