Hepatitis caused by micronized natural progesterone given for preterm labor

Micronized natural progesterone is often prescribed alone or in association with beta-agonists in the treatment of preterm labor in France, We observed drug-induced hepatitis in 4 such patients. The main manifestation of liver disease was pruritis, After drug withdrawal, elevated transaminase levels continued to rise for one week then normalized within 10 to 30 days. The imputability of this undesirable effect was assessed and considered to be likely. The effectiveness of micronized natural progesterone in the prevention of premature delivery and in decreasing perinatal mortality and morbidity has not yet been proven. This drug should therefore be used with care, keeping in mind the risk of hepatitis, particularly in patients presenting with pruritis.