###  Risk Summary

There are no adequate and well-controlled studies of budesonide and formoterol fumarate dihydrate inhalation aerosol or one of its individual components, formoterol fumarate, in pregnant women; however studies are available for the other component budesonide. In animal reproduction studies, budesonide and formoterol fumarate dihydrate, administered 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 fumarate alone, administered by the oral route, was teratogenic in rats and rabbits at 1600 and 65,000 times the MRHDID, respectively. Formoterol fumarate 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 fumarate 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.

The estimated background risk of major birth defects and miscarriage of the indicated populations is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

###  Clinical Considerations

#### 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 budesonide and formoterol fumarate dihydrate inhalation aerosol during labor and delivery. Because of the potential for beta-agonist interference with uterine contractility, use of BREYNA during labor should be restricted to those patients in whom the benefits clearly outweigh the risk.

###  Data

#### Human Data 

Studies of pregnant women have not shown that inhaled budesonide increases the risk of abnormalities when administered during pregnancy. The results from a large population-based prospective cohort epidemiological study reviewing data from three Swedish registries covering approximately 99% of the pregnancies from 1995-1997 (i.e., Swedish Medical Birth Registry; Registry of Congenital Malformations; Child Cardiology Registry) indicate no increased risk for congenital malformations from the use of inhaled budesonide during early pregnancy. Congenital malformations were studied in 2014 infants born to mothers reporting the use of inhaled budesonide for asthma in early pregnancy (usually 10-12 weeks after the last menstrual period), the period when most major organ malformations occur. The rate of recorded congenital malformations was similar compared to the general population rate (3.8% vs. 3.5%, respectively). In addition, after exposure to inhaled budesonide, the number of infants born with orofacial clefts was similar to the expected number in the normal population (4 children vs. 3.3, respectively).

These same data were utilized in a second study bringing the total to 2534 infants whose mothers were exposed to inhaled budesonide. In this study, the rate of congenital malformations among infants whose mothers were exposed to inhaled budesonide during early pregnancy was not different from the rate for all newborn babies during the same period (3.6%).

#### Animal Data 

Budesonide and Formoterol Fumarate Dihydrate Inhalation Aerosol

In an embryo-fetal development study in pregnant rats dosed during the period of organogenesis from gestation days 6-16, budesonide and formoterol fumarate dihydrate inhalation aerosol produced umbilical hernia in fetuses at doses less than the MRHDID (on a mcg/m2 basis at maternal inhaled doses of 12/0.66 mcg/kg/day and above). Fetal weights were reduced at approximately 5 and 3 times the MRHDID, respectively (on an AUC basis at a maternal inhaled dose of 80/4.4 mcg/kg (budesonide/formoterol)). No teratogenic or embryocidal effects were detected at doses less than the MRHDID (on a mcg/m2 basis at a maternal inhaled dose of 2.5/0.14 mcg/kg/day).

Budesonide

In a fertility and reproduction study, male rats were subcutaneously dosed for 9 weeks and females for 2 weeks prior to pairing and throughout the mating period. Females were dosed up until weaning of their offspring. Budesonide caused a decrease in prenatal viability and viability in the pups at birth and during lactation, along with a decrease in maternal body-weight gain, at doses less than the MRHDID (on a mcg/m2 basis at maternal subcutaneous doses of 20 mcg/kg/day and above). No such effects were noted at a dose less than the MRHDID (on a mcg/m2 basis at a maternal subcutaneous dose of 5 mcg/kg/day).

In an embryo-fetal development study in pregnant rabbits dosed during the period of organogenesis from gestation days 6-18, budesonide produced fetal loss, decreased fetal weight, and skeletal abnormalities at doses less than the MRHDID (on a mcg/m2 basis at a maternal subcutaneous dose of 25 mcg/kg/day). In an embryo-fetal development study in pregnant rats dosed during the period of organogenesis from gestation days 6-15, budesonide produced similar adverse fetal effects at doses approximately 8 times the MRHDID (on a mcg/m2 basis at a maternal subcutaneous dose of 500 mcg/kg/day). In another embryo- fetal development study in pregnant rats, no teratogenic or embryocidal effects were seen at doses up to 4 times the MRHDID (on a mcg/m2 basis at maternal inhalation doses up to 250 mcg/kg/day).

In a peri-and post-natal development study, rats dosed from gestation day 15 to postpartum day 21, budesonide had no effects on delivery, but did have an effect on growth and development of offspring. Offspring survival was reduced and surviving offspring had decreased mean body weights at birth and during lactation at doses less than the MRHDID and higher (on a mcg/m2 basis at maternal subcutaneous doses of 20 mcg/kg/day and higher). These findings occurred in the presence of maternal toxicity.

Formoterol

In a fertility and reproduction study, male rats were orally dosed for 9 weeks and females for 2 weeks prior to pairing and throughout the mating period. Females were either dosed up to gestation day 19 or up until weaning of their offspring. Males were dosed up to 25 weeks. Umbilical hernia was observed in rat fetuses at oral doses 1600 times and greater than the MRHDID (on a mcg/m2 basis at maternal oral doses of 3000 mcg/kg/day and higher). Brachygnathia was observed in rat fetuses at a dose 8000 times the MRHDID (on a mcg/m2 basis at a maternal oral dose of 15,000 mcg/kg/day). Pregnancy was prolonged at a dose 8000 times the MRHDID (on a mcg/m2 basis at a maternal oral dose of 15,000 mcg/kg/day). Fetal and pup deaths occurred at doses approximately 1600 times the MRHDID and higher (on a mcg/m2 basis at oral doses of 3000 mcg/kg/day and higher) during gestation.

In an embryo-fetal development study in pregnant rats dosed during the period of organogenesis from gestation days 6-15, no teratogenic, embryocidal or developmental effects were seen at doses up to 375 times the MRHDID (on a mcg/m2 basis with maternal inhalation doses up to 690 mcg/kg/day).

In an embryo-fetal development study in pregnant rabbits dosed during the period of organogenesis from gestation days 6-18, subcapsular cysts on the liver were observed in the fetuses at a dose 65,000 times the MRHDID (on a mcg/m2 basis with a maternal oral dose of 60,000 mcg/kg/day). No teratogenic effects were observed at doses up to 3800 times the MRHDID (on a mcg/m2 basis at maternal oral doses up to 3500 mcg/kg/day).

In a pre- and post-natal development study, pregnant female rats received formoterol at oral doses of 0, 210, 840, and 3400 mcg/kg/day from gestation day 6 through the lactation period. Pup survival was decreased from birth to postpartum day 26 at doses 110 times the MRHDID and higher (on a mcg/m2 basis at maternal oral doses of 210 mcg/kg/day and higher), although there was no evidence of a dose-response relationship. There were no treatment-related effects on the physical, functional, and behavioral development of rat pups.