Antenatal corticosteroid administration for enhancing fetal lung maturity can be expected to induce negative maternal and fetal side-effects. Maternal short-term effects after multiple courses of corticosteroids are an increase of infections and a higher incidence of endometritis and chorionamnionitis in patients with premature rupture of membranes. A single dose of corticosteroid induces an increase in the count of maternal white blood cells and metabolic effects such as the augmentation of amino acid concentration and of fasting glucose levels in maternal plasma. Negative fetal effects of antenatal corticosteroids are a reduction of fetal body and breathing movements and a reduction of fetal heart rate variation, without any changes in Doppler waveform patterns of fetoplacental vessels. It has been suggested that a multiple course of corticosteroids antenatally might induce negative effects on fetal intrauterine growth and on neonatal birth weight. In addition, multiple courses are associated with an increased risk of early-onset neonatal sepsis.