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2 fives for the nation for 1990.* But much more needs to be done. Congress, state governments, professional groups, business and labor organizations, church and women's groups, schools, and the media all have a role to play in improving the health of the nation's infants. The committee recommends that leadership in the effort to reduce the occurrence of Tow birthweight be assumed by the executive branch of the federal government, especially the ~. , . tJ ' 1 ~ Department or Realty and Human Services. Such leadership should include an increased commitment of resources to a range of activities likely to decrease low birthweight. The committee's conclusions and recommendations, and the data supporting them, have been published in a comprehensive report available from the National Academy Press. This summary volume is intended to provide a brief overview of the issues covered in the full report and is cTirected to health care practitioners, legislators and their staffs, government aciminis- trators, and all others interested in the prevention of low birthweight in infants. Support for the Committee to Study the Prevention of Low Birthweight was proviclecT principally by the Commonwealth Fund, with additional support from the Ford Foundation, the March of Dimes Birth Defects Foundation, the National Institute of Child Health and Human Develop- ment, and the National Research Council Fund. THE LOW BIRTHWEIGHT PROBLEM In 1982, 6. ~ percent of newborns in the United States were Tow birthweight (2,500 grams or less), and slightly more than ~ percent were very low birthweight (1,500 grams or less). Low birthweight is an indicator of inade- quate fetal growth, resulting from premature birth Duration of pregnancy less than 37 weeks from the last menstrual period), poor weight gain for a given duration of gestation (intrauterine growth retarclation), or both. To determine the consequences for child health of being born at Tow birthweight, the committee reviewed the literature on the relationships between low birthweight and both mortality and morbidity. Two-thircis of deaths in the neonatal period (the first 28 days of life) occur among infants born at 2,500 grams or less. The risk of mortality increases with decreasing birthweight the risk of neonatal death is 200 times greater for the very Tow birthweight infant than for the normal birthweight infant. The link between birthweight and death in the postneonatal period (be- tween 28 days and ~ year of age) is less pronounced, but still significant. Low birthweight infants are five times more likely than normal birthweight in- fants to die later in the first year and account for 20 percent of postneonatal deaths. High rates of low-weight births also contribute to differences in infant mortality found among particular groups of the population in the Unitecl States. For example, the higher neonatal mortality rates observed for non *"By 1990, low birthweight babies . . . should constitute no more than 5 percent of all live births . . . (and) no county and no racial or ethnic group of the population (e.g.. black, Hispanic, American Indian) should have a rate of low birth weight infants . . . that exceeds 9 percent of all live births."
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3 white mothers, adolescent mothers, and mothers with less than a high school education are largely explainecl by higher proportions of low birth- weight infants in these groups. For postneonatal mortality, the association is somewhat different. Even after controlling statistically for birthweight, postneonatal mortality rates remain higher for nonwhite infants, infants of teenage mothers, and infants of mothers of low educational attainment. Thus, factors typical of socioeco- nomic disadvantage are linked to increased infant mortality through both higher Tow birthweight rates and a birthweight-indepenclent risk of post- neonatal death. Current Trends Between 1965 and 19SO, the infant mortality rate in the United States dropped by almost 50 percent, from 24.7 to 13.] per 1,000 live births. This decrease has not been matched by a comparable clecline in the rate of Tow birthweight. Between 1971 and 1982, Tow-weight births declined moderately from 76 to 68 per 1,000 live births. Analysis of national and state data shows that the decline in low birthweight has been confined to the group weighing between 1,501 grams and 2,500 grams. No decline has been observed in the proportion of very low birthweight infants. Evidence from a variety of sources indicates that the recent decline in infant mortality, especially neonatal mortality, can be attributed largely to improved survival of low birthweight infants, resulting primarily from more speciaTizecl hospital-based management through neonatal intensive care programs. The moderate improvement in the Tow birthweight rate has played a relatively small role. Sustaining the decline in infant mortality will require major new actions to prevent Tow birthweight an approach that may well prove to be considerably less costly, both socially and economical- ly, than additional investments in neonatal intensive care. Low Birthweight and Morbidity Low birthweight infants appear to be at increased risk of a variety of health problems, although the impact of low birthweight on morbidity is less well established than its contribution to mortality. The association between low birthweight and neurodevelopmental prob- lems, such as cerebral palsy and seizure disorders, was first documented in the 1950s. Low birthweight infants are three times as likely as normal birth- weight infants to have neurodevelopmental handicaps, and the risk in- creases with decreasing birthweight ~ to 19 percent of very low birthweight infants may be severely affected. The risk of other developmental problems, especially those related to success in school, is more difficult to evaluate. it appears that these problems are more common among children whose birthweights were low for gesta- tional age, but the evidence is not conclusive. Low birthweight infants also are more likely to have significant congenital anomalies than normal birthweight infants and are more susceptible to conditions such as lower respiratory tract infections. They are also vuIner- able to the potential sicle effects of neonatal intensive care interventions. In