The situation in developing countries is very different. First, we want to be clear about the terms we will be using, because many policies and outcome studies use different measures. In analysis of perinatal

outcomes, the terms “preterm birth” and “low birth weight” are sometimes used almost interchangeably. Preterm birth is defined as birth before 37 weeks of gestation, measured from the first day of the pregnant woman’s last menstrual period. Low birth weight is defined as a weight less than 2,500 grams or about 5.5 pounds. Some babies are low-birth-weight without being preterm. Others are preterm but not low-birth-weight. Inhibitors,research,lifescience,medical Birth weight is easier to measure

accurately than is gestational age. Thus, much data and many policies focus on low birth weight because accurate gestational Inhibitors,research,lifescience,medical ages are often not available. THE DISMAL HISTORY OF EFFORTS TO REDUCE PRETERM BIRTH RATES For the 30 years prior to 2007, practitioners and policy-makers seemed powerless to reduce—or even stabilize—the rate of preterm birth in the United States. Between 1980 and 2006, the percentage Inhibitors,research,lifescience,medical of births that were preterm rose from 9.4% to 12.7%—a rise of nearly 30%.1 International comparisons further highlighted the failure of policy: the preterm rate in the United States is among the highest in the world and is similar to the rate Inhibitors,research,lifescience,medical in the least developed countries.2 The failure to reduce the rate of preterm birth over these years was not for lack of effort. Like a drum-beat, national commissions periodically recognized and highlighted preterm birth as a significant medical and public health problem. Their reports invariably set ambitious goals Inhibitors,research,lifescience,medical of reducing preterm birth or low birth weight in the foreseeable future and recommended concrete mechanisms for

achieving those goals. One of the first of such reports, from the Institute of Medicine (IOM) in 1985, was entitled “Preventing Low Birth Weight.” That report laid out the stark facts: Low birth weight is a major determinant of infant mortality in the United States … In addition to increasing the risk of mortality, low birth weight also increases Physiological Reviews the risk of illness … The association of neurodevelopmental handicaps and congenital anomalies with low birth weight has been well established; low birth weight infants also may be susceptible to a wide range of other conditions, such as lower respiratory tract infections, learning disorders, behavior CX-5461 mouse problems, and complications of neonatal intensive care interventions.3 The report argued that better access to prenatal care would lower the rate of low birth weight and preterm birth, and that programs to improve access to prenatal care would be cost-saving.