The Journal of Pediatrics
Volume 150, Issue 4 , Pages 428.e1-428.e2, April 2007

50 Years Ago in The Journal of Pediatrics:

Premature Infant Mortality

  • K.S. Joseph, MD, PhD

      Affiliations

    • Department of Obstetrics & Gynaecology and of Pediatrics, Dalhousie University and the IWK Health Centre, Halifax, Nova Scotia, Canada
    • ,
  • Michael S. Kramer, MD

      Affiliations

    • Departments of Pediatrics and of Epidemiology and Biostatistics, McGill University Faculty of Medicine, Montreal, Quebec, Canada

Article Outline

 

Corey JH Jr, Waddell WW Jr, Mitchell FN. J Pediatr 1957;50:340-4

Corey et al described the mortality experience of “premature” [sic] infants at the University of Virginia Hospital between 1949 and 1955. Temporal improvements in survival were attributed to the control of infection and hemorrhage, whereas the higher mortality rate among white infants compared with black infants was attributed to differences in “maturity.” Future improvements in survival were expected to “largely depend on prolongation of [the] gestational period.”

Infant mortality rates in the United States have declined sharply since 1957—from 26.0 in 1960 to 6.9 per 1000 live births in 20031—despite no progress in prolonging gestation. Reductions in mortality rates followed improvements in access to and quality of obstetric and neonatal care and have occurred across the entire birth weight and gestational age ranges. Deaths caused by Rh hemolytic disease of the newborn disappeared after the introduction of Rh immune globulin in 1968. After a period of stagnation in the 1980s,2 mortality rates declined in the 1990s following the introduction of antenatal maternal steroids, surfactant, food fortification with folic acid, prenatal diagnosis of congenital anomalies, and the back-to-sleep campaign for sudden infant death syndrome.

Our conceptualization of fetal growth and gestational duration has changed as well. Corey et al’s focus on “prematurity” (which the World Health Organization defined at the time as low [<2500 g] birth weight [LBW]) has been replaced by a dual focus on preterm birth and fetal growth restriction.3 The improved perspective is illustrated by the Canadian experience: LBW rates have declined slightly over the past 2 decades, although preterm birth rates have increased and small-for-gestational age rates have declined substantially.4

By the 1960s, the paradoxical survival advantage of LBW black infants was recognized to be a general phenomenon also seen among infants of smokers, twins, etc. Wilcox and Russell5 proposed a creative “relative birth weight” solution to the paradox in the mid 1980s. More recently, the “fetuses-at-risk approach,”6 which redefines the denominator to include all fetuses at risk for perinatal events, has been proposed to resolve the paradox. The fetuses-at-risk approach also demonstrates the links in gestational age-specific risks of birth, fetal growth restriction, and perinatal death.7

How will perinatal health advance in the years to come? We do not appear to have fully grasped the consequences of recent successes in reducing mortality rates. Follow-up studies of extremely preterm infants show high rates of cerebral palsy, poor vision, and neurodevelopmental problems.8 Society should invest in the clinical and community infrastructure to meet the needs of such children.

References available at www.jpeds.com

Back to Article Outline

References 

  1. Hoyert DL, Heron MP, Murphy SL, Kung H. Deaths: Final Data for 2003. National vital statistics reports. Hyattsville, MD: National Center for Health Statistics; 2006;vol 54 no 13.
  2. Kleinman JC. The slowdown in the infant mortality decline. Paediatr Perinat Epidemiol. 1990;4:373–381
  3. Kramer MS. Determinants of low birth weight: methodologic assessment and meta-analysis. Bull WHO. 1987;65:663–737
  4. Canadian Perinatal Health Report 2003. Health Canada. Ottawa: Minister of Public Works and Government Services Canada; 2003;
  5. Wilcox AJ, Russell IT. Why small black infants have lower mortality than small white infants: the case for population-specific standards for birth weight. J Pediatr. 1990;116:7–10
  6. Joseph KS, Demissie K, Platt RW, Ananth CV, McCarthy BJ, Kramer MS Canadian Perinatal Surveillance System. A parsimonious explanation for intersecting perinatal mortality curves: understanding the effects of race and of maternal smoking. BMC Pregnancy Childbirth. 2004;4:7
  7. Joseph KS. Incidence-based measures of birth, growth restriction and death can free perinatal epidemiology from erroneous concepts of risk. J Clin Epidemiol. 2004;57:889–897
  8. Hack M, Taylor HG, Drotar D, Schluchter M, Cartar L, Andreias L, et al. Chronic conditions, functional limitations, and special health care needs of school-aged children born with extremely low-birth-weight in the 1990s. JAMA. 2005;294:318–325

PII: S0022-3476(06)01035-3

doi:10.1016/j.jpeds.2006.10.066

The Journal of Pediatrics
Volume 150, Issue 4 , Pages 428.e1-428.e2, April 2007

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