In animal reproduction studies, administration of budesonide-formoterol by the inhalation route, was teratogenic, embryocidal, and reduced fetal weights in rats at less than the maximum recommended human daily inhalation dose (MRHDID) on a mcg/m2 basis.

Budesonide alone, administered by the subcutaneous route, was teratogenic, embryocidal, and reduced fetal weights in rats and rabbits at less than the MRHDID, but these effects were not seen in rats that received inhaled doses up to 4 times the MRHDID. Studies of pregnant women have not shown that inhaled budesonide alone increases the risk of abnormalities when administered during pregnancy. Experience with oral corticosteroids suggests that rodents are more prone to teratogenic effects from corticosteroid exposure than humans.

Formoterol alone, administered by the oral route, was teratogenic in rats and rabbits at 1600 and 65,000 times the MRHDID, respectively. Formoterol was also embryocidal, increased pup loss at birth and during lactation, and decreased pup weight in rats at 110 times the MRHDID. These adverse effects generally occurred at large multiples of the MRHDID when formoterol was administered by the oral route to achieve high systemic exposures. No teratogenic, embryocidal, or developmental effects were seen in rats that received inhalation doses up to 375 times the MRHDID.

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.

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

AU TGA pregnancy category: B3
US FDA pregnancy category: Not assigned.

Risk Summary:
-There are no adequate and well-controlled studies of this drug or one of its individual components, formoterol, in pregnant women.
-Disease-Associated Maternal and/or Embryo/Fetal risk: In women with poorly or moderately controlled asthma, there is an increased risk of several perinatal adverse outcomes such as preeclampsia in the mother and prematurity, low birth weight, and small for gestational age in the neonate. Pregnant women with asthma should be closely monitored and medication adjusted as necessary to maintain optimal asthma control.
-Labor or Delivery: There are no well-controlled human studies that have investigated the effects of this drug during labor and delivery. Due to the potential for beta-agonist interference with uterine contractility, this drug should be used during labor only if the benefits clearly outweigh the risk.

See references

Budesonide:
Human data with dry powder inhaler indicates that the total daily oral dose available in breast milk to the infant is approximately 0.3% to 1% of the dose inhaled by the mother.

Formoterol:
In the fertility and reproduction study in rats, the maximum plasma concentration that the pups received from the maternal animal after nursing was estimated at 4.4%.

A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.

Excreted into human milk: Yes (budesonide); Unknown (formoterol)
Excreted into animal milk: Yes (formoterol); Data not available (budesonide)

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

See references