In writing this review, we did a Medline search for articles reported over the past decade. We used the following medical subject headings to search for articles: “premature”, “preterm”, “low birthweight”, “follow-up”, “cerebral palsy”, and “outcomes”. We focused on studies that reported comprehensive, long-term outcomes in geographically-defined cohorts, with few or no exclusions because they are likely to be least biased.
SeriesAn overview of mortality and sequelae of preterm birth from infancy to adulthood
Introduction
As Goldenberg and colleagues1 outline earlier in this series, the rate of preterm birth in developed countries has risen, rather than fallen, over time. Moreover, the survival rates for very early preterm births have increased because of technological advances and the collaborative efforts of obstetricians and neonatologists. However, biologically, preterm infants are more susceptible than are their term counterparts. Although most organs are immature, the brain2 and lung3 are especially susceptible to the consequences of preterm birth, which leads to high rates of long-term neurological and health problems. Because of increasing costs of providing neonatal intensive care and social and economic burden of disabilities, the debate continues about whether intensive care is justified for infants of borderline viability. Clinicians will increasingly be exposed to survivors of preterm birth; therefore, they need to be aware of the changing outcomes and the long-term effect of disabilities and health problems on the survivors, their families, and society.
Here we review data for the mortality and both short-term and long-term sequelae of preterm birth in developed countries. The focus will be on a broad range of outcomes, such as neurodevelopment, education, behaviour, psychosocial matters, growth, and health of the most preterm (<30 or <32 weeks' gestational age) infants, at various ages from infancy through to adulthood. Whenever possible, we will add the few data available for similar outcomes in infants closer to term, sometimes referred to as late preterm births.4 For most outcomes, we will rely on the more plentiful data reported by birthweight, either for infants of very low birthweight (VLBW, birthweight <1500 g) or extremely low birthweight (ELBW, birthweight <1000 g).
The methodological issues that prevent valid comparisons of outcomes between different centres and different countries include heterogeneity of the cohorts under consideration (geographically-defined vs multicentre vs single-centre studies); reporting of outcomes by birthweight versus gestational age; varying ages of reporting outcomes; different assessment techniques; inconsistencies in the definitions and severity of reporting disabilities; and high attrition rates.5, 6
Section snippets
Late preterm births
Although preterm births at 32–36 weeks' gestation are five times more common than births before 32 weeks' gestation, their public-health effect has not been well studied.7 In 2003, 12·3% of births in the USA were preterm (defined as <37 weeks' gestation).4 What is of concern is that since 1981 there has been a 31% increase in the preterm birth rate in the USA, of which two-thirds were late preterm births (34–36 completed weeks' gestation).8
The mortality and neonatal morbidity of late preterm
Conclusions
Although work on strategies for prevention or reduction, or both, of the frequency of prematurity continues, future directions for neonatologists include modifying the antecedents of brain injury, achieving the best neonatal and postnatal care for infants, and providing greater support and resources to parents to help them achieve the best potential for their children. Additionally, further prospective long-term follow-up to middle age is warranted to establish whether preterm infants are at
Search strategy and selection criteria
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