Preterm delivery is currently the leading cause of perinatal morbidity and mortality. PROM is the most common easily identifiable cause of preterm delivery, present in 20-30% of preterm births. The conflicting results of success in prematurity prevention programs obtained by different investigators probably reflect the populations that were studied. Meis and colleagues divided the etiologies of low birth weight into four categories: 1) Low birth weight in infants greater than 37 weeks' gestation, 2) PROM, 3) birth weight caused by medical complications, and 4) idiopathic premature labor (IPL). In patients seen in the county health department clinic (1,529 births), IPL accounted for 25% of birth weights less than 2,500 g. In contrast, patients seen in a large private obstetric practice (1,327 births), IPL was the etiology of low birth weight in 47% of patients. Not surprisingly, a prematurity prevention program has not reduced the rate of low birth weight for the public patients but has resulted in decreases of low birth weight for the private patients. Paramount in the prevention of preterm birth is physician education regarding known risk factors, signs and symptoms of preterm labor, and the role of close follow-up in the patients identified as high risk. Papiernik's success with limitation of physical efforts and work leave, when appropriate, in high-risk patients is laudable and, many feel, should be emulated. Prenatal care must include for each woman education concerning the signs and symptoms of preterm labor and PROM. Individual risk factors must be ascertained and followed with appropriate observation, therapy, and/or modification plans. Finally, the early detection of preterm labor will expedite prompt treatment and so increase chances of postponing delivery.