Studies have show that daily use of almost all types of inhaled corticosteroid drugs while pregnant (at normal dosage) do not cause birth defects or other problems. However, animal studies have demonstrated that oral and intravenous use of corticosteroids during pregnancy can cause birth defects. Using a higher dosage of corticosteroids has also been shown to cause unwanted effects during a pregnancy, including slower infant growth and adrenal gland problems. These problems were more likely to occur if the higher dosage was taken in the first trimester.

Nasal corticosteroids are generally considered to be safer than intravenous or oral corticosteroids. Using a nasal corticosteroid in place of an oral or intravenous corticosteroid during pregnancy is often recommended by a physician, when possible.

Most physicians agree that the rewards of using corticosteroids on some types of conditions (e.g., asthma) often outweigh the risks. However, pregnant women should always discuss the use of corticosteroids with their physicians before using the medication.

Breastfeeding women should exercise caution when nursing. While most types of corticosteroids do pass into breast milk, they are generally present at such low levels that it does not affect the infant. However, the corticosteroid dexamethasone has been linked to slow growth in nursing infants when used by the mother. Breastfeeding mothers should consult their physicians before taking corticosteroids.