Abstract
Preterm birth is the major cause of perinatal morbidity and mortality in the developed world, and spontaneous preterm labor is the commonest cause of preterm birth. Interventions to treat women in spontaneous preterm labor have not reduced the incidence of preterm births but this may be due to increased risk factors, inclusion of births at the limits of viability, and an increase in the use of elective preterm birth. The role of antibiotics remains unproven. In the largest of the randomized controlled trials, evaluating the use of antibiotics for the prevention of preterm births in women in spontaneous preterm labor, antibiotics against anaerobes and bacterial vaginosis-related organisms were not included, and no objective evidence of abnormal genital tract flora was obtained. Atosiban and nifedipine are the main tocolytic agents used to treat women in spontaneous preterm labor, but atosiban is the tocolytic agent with the fewest maternal - fetal side effects. A well conducted randomized controlled trial comparing atosiban with nifedipine for their effectiveness and safety is needed.