Risk Summary

Mometasone is minimally absorbed systemically following nasal use, and maternal use is not expected to result in fetal exposure to the drug. Available data from observational studies of mometasone use in pregnant women are insufficient to evaluate for a drug-associated risk of major birth defects, miscarriage or other adverse maternal or fetal outcomes. In animal reproduction studies with pregnant mice, rats, or rabbits (subcutaneous, subcutaneous/topical dermal/oral, and topical dermal/oral, respectively), mometasone furoate caused increased fetal malformations and decreased fetal survival and growth following administration of doses that produced exposures approximately 1/3 to 8 times the maximum recommended human dose (MRHD) on a mcg/m2 or AUC basis [see Data]. However, experience with oral corticosteroids suggests that rodents are more prone to teratogenic effects from corticosteroid exposure than humans. 

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. 

Data 

Animal Data 

In an embryofetal development study with pregnant mice dosed throughout the period of organogenesis, mometasone furoate produced cleft palate at a dose less than the maximum recommended daily intranasal dose (MRDID) (on a mcg/m2 basis with maternal subcutaneous doses of 60 mcg/kg and above) and decreased fetal survival at approximately 2 times the MRDID (on a mcg/m2 basis with a maternal subcutaneous dose of 180 mcg/kg). No toxicity was observed with a dose that produced an exposure less than the MRDID (on a mcg/m2 basis with maternal topical dermal doses of 20 mcg/kg and above). 

In an embryofetal development study with pregnant rats dosed throughout the period of organogenesis, mometasone furoate produced fetal umbilical hernia at exposures approximately 10 times the MRDID (on a mcg/m2 basis with maternal topical dermal doses of 600 mcg/kg and above) and delays in fetal ossification at a dose approximately 6 times the MRDID (on a mcg/m2 basis with maternal topical dermal doses of 300 mcg/kg and above). 

In another reproductive toxicity study, pregnant rats were dosed with mometasone furoate throughout pregnancy or late in gestation. Treated animals had prolonged and difficult labor, fewer live births, lower birth weight, and reduced early pup survival at a dose less than the MRDID (on a mcg/m2 basis with a maternal subcutaneous dose of 15 mcg/kg). There were no findings at a dose less than the MRDID (on a mcg/m2 basis with a maternal subcutaneous dose of 7.5 mcg/kg). 

Embryofetal development studies were conducted with pregnant rabbits dosed with mometasone furoate by either the topical dermal route or oral route throughout the period of organogenesis. In the study using the topical dermal route, mometasone furoate caused multiple malformations in fetuses (e.g., flexed front paws, gallbladder agenesis, umbilical hernia, hydrocephaly) at doses approximately 6 times the MRDID (on a mcg/m2 basis with maternal topical dermal doses of 150 mcg/kg and above). In the study using the oral route, mometasone furoate caused increased fetal resorptions and cleft palate and/or head malformations (hydrocephaly and domed head) at a dose approximately 30 times of the MRDID (on a mcg/m2 basis with a maternal oral dose of 700 mcg/kg). At approximately 110 times the MRDID (on a mcg/m2 basis with a maternal oral dose of 2800 mcg/kg), most litters were aborted or resorbed. No effects were observed at a dose approximately 6 times the MRDID (on a mcg/m2 basis with a maternal oral dose of 140 mcg/kg).