Neither inhaled mometasone, mometasone nasal spray, nor mometasone nasal implants have been studied during breastfeeding. Although not measured, the amounts of inhaled and nasal corticosteroids absorbed into the maternal bloodstream and excreted into breastmilk are probably too small to affect a breastfed infant. Expert opinion considers inhaled, nasal and oral corticosteroids acceptable to use during breastfeeding.[1,2] See also Mometasone, Topical.