This drug has not been tested for developmental toxicity in pregnant animals. In animals given interferon beta by subcutaneous injection every other day during early pregnancy, no teratogenic or other adverse effects on fetal development were observed. Abortifacient activity was evident following 3 to 5 doses.

AU TGA pregnancy category D: Drugs which have caused, are suspected to have caused or may be expected to cause, an increased incidence of human fetal malformations or irreversible damage. These drugs may also have adverse pharmacological effects. Accompanying texts should be consulted for further details.

US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

This drug should be used during pregnancy only if the benefit outweighs the risk.

AU TGA pregnancy category: D
US FDA pregnancy category: C

Comments:
-Some experts consider initiating therapy during pregnancy to be contraindicated.

See references

Caution is recommended.

Excreted into human milk: Unknown
Excreted into animal milk: Data not available

Comments:
-The effects in the nursing infant are unknown.

-Although no information is available on this drug in breastmilk, the levels of conventional interferon beta-1a in breastmilk are minuscule. Because interferon is poorly absorbed orally, it is not likely to reach the bloodstream of the infant. A small number of nursing mothers receiving interferon beta-1a while partially breastfeeding their infants and one woman exclusively breastfed her infant while taking interferon beta-1b and reported no adverse effects.
-The Multiple Sclerosis Centre of Excellence on Reproduction and Child Health considers interferon beta to be "moderately safe" to use during breastfeeding.

See references