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Preterm birth: crisis and opportunity
Editorial
The health of much of the developed world has improved in recent years, thanks to social and medical advances, including improved diagnostics and therapeutics. But in the USA, at least one important public-health problem, preterm birth, has worsened in the past decade. The US Institute of Medicine (IOM), in a report released on July 18, said that 9·4% of births occurred before 37 weeks of gestation in 1981. But since then, the rate has risen by more than 30%, and now preterm births account for 12·5% of all births. This proportion, which is unacceptably high, looks even worse when broken down by race, ethnic group, and socioeconomic status. The highest rates of preterm birth occur among racial and ethnic minorities, especially African-Americans (17·8% vs 11·5% for white women). Preterm birth rates are also higher for Hispanic women (11·9%), and American Indians and native Alaskans (13·5%), than for white women. Advances in perinatal and neonatal care have reduced the mortality due to preterm birth, but morbidity remains a serious problem. Infants born early are at high risk for developmental problems, birth defects, cerebral palsy, mental retardation, visual impairment, hearing loss, and other, sometimes less obvious, central nervous system disorders, including language and learning disabilities, attention-deficit hyperactivity disorder, and behavioural problems. The cost to society of these complications was more than US$26·2 billion in 2005, or $51 600 for each infant born early, with the cost of medical care accounting for two-thirds of this amount. The rest of the price tag is mainly an estimate because little is known about the actual costs of preterm birth beyond inpatient care and first hospitalisation. A good deal of money is thought to be spent on early intervention programmes, special education, and lost productivity by parents and other caregivers. And, of course, the cost of preterm birth is not merely economic. Preterm birth also exacts an enormous physical, emotional, and psychological toll on families. Why has preterm birth increased, and what can be done about it? The IOM report notes a paucity of published work on the prevention, diagnosis, and treatment of preterm birth. It suggests that the causes are complex and multifactorial, and that solutions must be equally wide-ranging. Some contributing factors are social and economic (lack of access to prenatal care, stress, major www.thelancet.com Vol 368 July 29, 2006
life events); some are biological (inflammation and infection, maternal stress, uteroplacental thrombosis, and intrauterine vascular lesions); some are behavioural (use of tobacco, alcohol, and illicit drugs, particularly cocaine); and some reflect genetic susceptibility and interactions between genes and the environment. Environmental exposures (especially to lead, tobacco smoke, sulphur dioxide, and particulate matter) may increase the risk of preterm birth. In addition, the huge rise in assisted reproductive technologies over the past two decades has resulted in delayed childbearing by older mothers and multiple gestations, which increase the risk of preterm delivery. This dismayingly long and far from definitive list has one quirky advantage. It provides many opportunities for multidisciplinary research, particularly clinical research, which is currently severely underfunded, given the severity of the problem. Urgent research priorities fall into several categories: better definition of the problem, through national data collection; health-services research, designed to investigate and improve and quality of care for women and infants at risk; and documentation of the causes and epidemiology of preterm birth. Better and more accurate data on gestational age are needed, which, the IOM report notes, can often be provided by early prenatal (at less than 20 weeks of gestation) ultrasound. Also needed are the development of a scheme that would classify preterm birth according to its aetiology, documentation of fertility treatments (with a view towards the development of guidelines to reduce the number of multiple gestations), comprehensive economic evaluation of the consequences of preterm birth, and early identification of and treatment for women at risk. At present, treatment of symptomatic preterm labour, rather than prediction and prevention, is the primary method of dealing with preterm birth. In part because preterm birth is a complex issue that frequently involves populations at the margins of mainstream society, research into its causes and solutions has up until now fallen short. The IOM report lays out a clear roadmap for the questions that must be answered to decrease the incidence of preterm birth. Such research should be given priority, funded, and undertaken without delay. The health of future generations depends on it. ■ The Lancet
We do not have the rights to reproduce this image on the web.
For the IOM report on preterm birth see http://newton.nap. edu/catalog/11622.html#toc
339
Science Photo Library
Preterm birth: crisis and opportunity
The health of much of the developed world has improved in recent years, thanks to social and medical advances, including improved diagnostics and therapeutics. But in the USA, at least one important public-health problem, preterm birth, has worsened in the past decade. The US Institute of Medicine (IOM), in a report released on July 18, said that 9·4% of births occurred before 37 weeks of gestation in 1981. But since then, the rate has risen by more than 30%, and now preterm births account for 12·5% of all births. This proportion, which is unacceptably high, looks even worse when broken down by race, ethnic group, and socioeconomic status. The highest rates of preterm birth occur among racial and ethnic minorities, especially African-Americans (17·8% vs 11·5% for white women). Preterm birth rates are also higher for Hispanic women (11·9%), and American Indians and native Alaskans (13·5%), than for white women. Advances in perinatal and neonatal care have reduced the mortality due to preterm birth, but morbidity remains a serious problem. Infants born early are at high risk for developmental problems, birth defects, cerebral palsy, mental retardation, visual impairment, hearing loss, and other, sometimes less obvious, central nervous system disorders, including language and learning disabilities, attention-deficit hyperactivity disorder, and behavioural problems. The cost to society of these complications was more than US$26·2 billion in 2005, or $51 600 for each infant born early, with the cost of medical care accounting for two-thirds of this amount. The rest of the price tag is mainly an estimate because little is known about the actual costs of preterm birth beyond inpatient care and first hospitalisation. A good deal of money is thought to be spent on early intervention programmes, special education, and lost productivity by parents and other caregivers. And, of course, the cost of preterm birth is not merely economic. Preterm birth also exacts an enormous physical, emotional, and psychological toll on families. Why has preterm birth increased, and what can be done about it? The IOM report notes a paucity of published work on the prevention, diagnosis, and treatment of preterm birth. It suggests that the causes are complex and multifactorial, and that solutions must be equally wide-ranging. Some contributing factors are social and economic (lack of access to prenatal care, stress, major www.thelancet.com Vol 368 July 29, 2006
life events); some are biological (inflammation and infection, maternal stress, uteroplacental thrombosis, and intrauterine vascular lesions); some are behavioural (use of tobacco, alcohol, and illicit drugs, particularly cocaine); and some reflect genetic susceptibility and interactions between genes and the environment. Environmental exposures (especially to lead, tobacco smoke, sulphur dioxide, and particulate matter) may increase the risk of preterm birth. In addition, the huge rise in assisted reproductive technologies over the past two decades has resulted in delayed childbearing by older mothers and multiple gestations, which increase the risk of preterm delivery. This dismayingly long and far from definitive list has one quirky advantage. It provides many opportunities for multidisciplinary research, particularly clinical research, which is currently severely underfunded, given the severity of the problem. Urgent research priorities fall into several categories: better definition of the problem, through national data collection; health-services research, designed to investigate and improve and quality of care for women and infants at risk; and documentation of the causes and epidemiology of preterm birth. Better and more accurate data on gestational age are needed, which, the IOM report notes, can often be provided by early prenatal (at less than 20 weeks of gestation) ultrasound. Also needed are the development of a scheme that would classify preterm birth according to its aetiology, documentation of fertility treatments (with a view towards the development of guidelines to reduce the number of multiple gestations), comprehensive economic evaluation of the consequences of preterm birth, and early identification of and treatment for women at risk. At present, treatment of symptomatic preterm labour, rather than prediction and prevention, is the primary method of dealing with preterm birth. In part because preterm birth is a complex issue that frequently involves populations at the margins of mainstream society, research into its causes and solutions has up until now fallen short. The IOM report lays out a clear roadmap for the questions that must be answered to decrease the incidence of preterm birth. Such research should be given priority, funded, and undertaken without delay. The health of future generations depends on it. ■ The Lancet
We do not have the rights to reproduce this image on the web.
For the IOM report on preterm birth see http://newton.nap. edu/catalog/11622.html#toc
339
Science Photo Library
Preterm birth: crisis and opportunity