Research
Obstetrics
Trends in neonatal morbidity and mortality for very low birthweight infants

https://doi.org/10.1016/j.ajog.2006.09.014Get rights and content

Objective

To document the mortality and morbidity of infants weighing 501-1500 g at birth according to gestational age, birthweight, and sex.

Study design

Prospective collection of perinatal events and neonatal course to 120 days of life, discharge, or death from January 1990 through December 2002 for infants born at 16 participating centers of the National Institute of Child Health & Human Development Neonatal Research Network.

Results

Compared with 1995-1996, for 1997-2002 the survival of infants with birthweight of 501-1500 g increased by 1 percentage point (from 84% to 85%). Survival without major neonatal morbidity remained static, at 70%; this includes bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), and necrotizing enterocolitis (NEC). Survival increased for multiple births (26%, up from 22%), antenatal corticosteroid use (79%, up from 71%), and maternal antibiotics (70%, up from 62%) (P < .05). From 1997 to 2002, birthweight-specific survival was 55% for infants weighing 501-750 g, 88% for 751-1000 g, 94% for 1001-1250 g, and 96% for 1251–1500 g. More females survived. The incidence of NEC (7%), severe IVH (12%), and late-onset septicemia (22%) remained essentially unchanged, but BPD decreased slightly, from 23% to 22%. The use of postnatal corticosteroids declined from 20% in 1997-2000 to 12% in 2001-2002. Growth failure (weight <10th percentile) at 36 weeks’ postmenstrual age decreased from 97% in 1995-1996 to 91% in 1997-2002.

Conclusion

There have been no significant increases in survival without neonatal and long-term morbidity among VLBW infants between 1997 and 2002. We speculate that to improve survival without morbidity requires determining, disseminating, and applying best practices using therapies currently available, and also identifying new strategies and interventions.

Section snippets

Materials and Methods

The present study compared perinatal information, morbidities, and mortality for 3 cohorts of infants born at participating centers (hereafter called “inborn infants”), all with birthweights between 501 and 1500 g. Cohort I comprises births in 1990 and 1991, the immediate postsurfactant era. Cohort II, comprising births in 1995 and 1996, reflects the sharp increase in antenatal corticosteroid use. Cohort III, with 18,153 infants, covers the period from 1997 to 2002.

All the infants were part of

Survival and morbidity

Mortality and selected morbidities among VLBW infants were compared for the 3 cohorts (1990-1991, 1995-1996, and 1997-2002), using data only from the 12 centers that had participated in the Network throughout this period. Mortality for the entire cohort declined from 20% in the 1990-1991 cohort to 16% (relative decline 20%, P < .0001) in the 1995-1996 cohort, and 15% (relative decline 6%, P = .9117) in the 1997-2002 cohort. Most deaths occurred within 7 days of birth, and 87% of VLBW infants

Comment

This report summarizes the mortality and morbidity among VLBW infants born at the Neonatal Research Network centers (listed under Acknowledgments) between 1997 and 2002. Comparison of outcomes for the full period from 1990 to 2002 is restricted to the 12 centers that participated throughout the 13 years. Between January 1997 and December 2002, 85% of inborn VLBW infants survived to discharge, ranging from 55% of infants who were 501-750 g at birth to 96% for infants 1250-1500 g at birth;

Acknowledgments

Membership of the NICHD Neonatal Research Network is as follows (principal investigators are indicated by an asterisk).

Chairman: Alan Jobe,* MD, University of Cincinnati

Case Western Reserve University (U10 HD021364): Avroy A. Fanaroff,* MD; Michele C. Walsh, MD; Nancy Newman, RN

University of Cincinnati (U10 HD027853, M01 RR008084): Edward F. Donovan,* MD; Marcia Mersmann, RN

Emory University (U10 HD027851): Barbara J. Stoll,* MD; Ellen Hale, RN

Indiana University (U10 HD027856, M01 RR000750):

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  • Cited by (0)

    Supported by a grant from the National Institutes of Health, National Institute of Child Health and Human Development, through cooperative agreements with the authors’ institutions U01 HD036790, U10 HD021364, U10 HD021373, U10 HD021385, U10 HD021397, U10 HD021415, U10 HD027851, U10 HD027853, U10 HD027856, U10 HD027871, U10 HD027880, U10 HD027881, U10 HD027904, U10 HD034167 U10 HD034216, and U10 HD040689, and General Clinical Research Centers M01 RR000070, M01 RR000750, M01 RR000997, M01 RR001032, M01 RR002172, M01 RR002635, M01 RR006022, and M01 RR008084.

    Cite this article as: Fanaroff AA, Stoll BJ, Wright LL, et al; NICHD Neonatal Research Network. Trends in neonatal morbidity and mortality for very low birthweight infants. Am J Obstet Gynecol 2007;196:147.e1-147.e8.

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