Dexamethasone has also been used during pregnancy as an off-label prenatal treatment for the symptoms of congenital adrenal hyperplasia (CAH) in female fetuses. CAH causes a variety of physical abnormalities, notably ambiguous genitalia in girls. Early prenatal CAH treatment has been shown to reduce some CAH symptoms, but it does not treat the underlying congenital disorder . This use is controversial: it is inadequately studied, only around one in ten of the foetuses of women treated are at risk of the condition, and serious adverse events have been documented.  Experimental use of dexamethasone in pregnancy for foetal CAH treatment was discontinued in Sweden when one in five cases suffered adverse events. 
Side effects are minimized by taking the lowest doses possible (that still yields positive results) and following doctor's orders. It is important to avoid self-regulation of the dosage, either by adding more or stopping the drug without a schedule. After prolonged use, steroids must be gradually reduced to permit the adrenal glands to resume natural cortisol production. Eliminating doses too quickly can result in glucocorticoid withdrawal symptoms, worsening of underlying inflammatory disease (rebound effect), or rarely, adrenal crisis (a life-threatening state caused by insufficient levels of adrenal steroids).