The challenges and unresolved dilemmas of prematurity.

ern medicine. In USA, prematurity accounts for more than 12% of all live newborn infants, a 20% increase from 1990. The same trend has been observed in most high income countries, including Eastern Europe countries, Japan, Australia and Canada, even when rates are lower. As an example of the extent of this problem, USA currently ranks 131 out of 184 countries worldwide in the prematurity rate ranking. What is the explanation for this? Is it possible to have an increased prematurity rate, similar to that observed in many low income and low resource settings, in a country that has made the most contributions to research and medical advances? This scenario points out the challenges and problems of prematurity. One of these depends only partially on medicine, the other falls entirely under the responsibility of the medical field, particularly the care provided at neonatal intensive care units (NICU) to premature infants born in the limits of viability. As demonstrated, the first of these approaches is related to health and is mainly originated in the living conditions of individuals, the effectiveness of measures taken by governments, the education and culture and, to a lesser extent, medicine; the second approach originates in medical ethical principles. Both approaches are highly complex and different. I will describe only the most relevant aspects of each one. The study of human physiology is based on the assumption that births occur at 40 weeks of gestation, with little variation. Yet, it has not been possible to certainly establish if preterm birth mechanisms are equal to those of term births and only take place earlier than expected, or if a preterm birth actually triggers different mechanisms. Several studies have demonstrated that social factors, including poverty, scarce maternal education, adolescent pregnancy, single motherhood, alcohol use, smoking, etc., substantially increase the risk of prematurity. In addition, these social, economic and cultural determinants account for maternal biologic factors, such as low weight and height, and/or a poor nutritional status during pregnancy, which are also associated with a higher risk of prematurity. The mother’s ethnicity is also a consistent risk factor. In USA, the prematurity rate in the AfricanAmerican population doubles that of Caucasians, and recurrent preterm births are four times more The challenges and unresolved dilemmas of prematurity