Morbidity and mortality among very-low-birth-weight neonates with intrauterine growth restriction,☆☆

https://doi.org/10.1016/S0002-9378(00)70513-8Get rights and content

Abstract

Objective: We sought to determine the associations between intrauterine growth restriction and neonatal morbidity and mortality, as well as the impact of prenatal glucocorticoid administration on the frequency of specific complications of prematurity among neonates with intrauterine growth restriction. Study Design: We examined the association between intrauterine growth restriction and adverse neonatal outcomes in a population of 19,759 singleton very-low-birth-weight neonates without major birth defects. We included neonates from 25 to 30 weeks’ gestation entered in the Vermont Oxford Network database between 1991 and 1996 by 196 institutions. Intrauterine growth restriction was defined as the 10th percentile for birth weight according to the 1993 US national statistics. Odds ratios were estimated according to stepwise logistic regression for each neonatal outcome. Potential explanatory variables included gestational age, intrauterine growth restriction, race, prenatal care, prenatal glucocorticoid administration, route of delivery, fetal sex, and birth within versus postnatal transfer to a network institution. Results: There was a statistically significant association of intrauterine growth restriction with neonatal death (odds ratio, 2.77; 95% confidence interval, 2.31-3.33), necrotizing enterocolitis (odds ratio, 1.27; 95% confidence interval, 1.05-1.53), and respiratory distress syndrome (odds ratio, 1.19; 95% confidence interval, 1.03-1.36). There was a trend (P < .10) toward association of intrauterine growth restriction with increased risks of intraventricular hemorrhage (odds ratio, 1.13; 95% confidence interval, 0.99-1.29) and severe intraventricular hemorrhage (grades III and IV; odds ratio, 1.25; 95% confidence interval, 0.98-1.59). Maternal prenatal glucocorticoid administration was associated with significantly lower risks of respiratory distress syndrome (odds ratio, 0.51; 95% confidence interval, 0.44-0.58), intraventricular hemorrhage (odds ratio, 0.67; 95% confidence interval, 0.61-0.73), severe intraventricular hemorrhage (odds ratio, 0.50; 95% confidence interval, 0.43-0.57), and death (odds ratio, 0.54; 95% confidence interval, 0.48-0.62). The benefits of prenatal glucocorticoid therapy for growth-restricted newborns were similar to those among normally grown infants. Conclusions: Intrauterine growth restriction within the range of 501 to 1500 g birth weight is associated with increased risks of neonatal death, necrotizing enterocolitis, and respiratory distress syndrome. Prenatal corticosteroid use was associated with decreased risks of all outcomes studied except necrotizing enterocolitis. We found no evidence that this benefit was dependent on fetal size. (Am J Obstet Gynecol 2000;182:198-206.)

Section snippets

Methods

We examined the morbidity and mortality associated with IUGR within the Vermont Oxford Network database.15 Neonates with birth weights between 501 and 1500 g are enrolled in the database if they are either born at a participating institution or transferred there within 28 days of birth. This database enrolled 49,335 neonates between 1991 and 1996 at 212 participating institutions. Additional details regarding this database have been previously published.15 Entries to the database are screened

Results

Nine percent (n = 1720) of the infants in the study population were found to have IUGR according to the modified US Center for Health Statistics natality database. Ten percent of the neonates enrolled for this project died before discharge. Ninety-four percent of the enrolled infants underwent neonatal cranial ultrasonographic examinations, and the incidence of intraventricular hemorrhage was 28%. The incidence of severe intraventricular hemorrhage (intraventricular hemorrhage grade III or IV)

Comment

The specific risk attributable to IUGR in the morbidity of neonates has been difficult to isolate. Data consistently demonstrate an increase in gestational age–corrected mortality rate among infants with IUGR, but morbidity risks have varied widely. One potential explanation for this discrepancy is the degree to which potential confounding variables are accounted for. In an initial report that suggested a protective effect of IUGR against intraventricular hemorrhage and RDS, Procianoy et al2

Acknowledgements

Participating investigators in the Vermont Oxford Network and their institutional affiliations are as follows:

  • Huntsville Hospital, Huntsville, AL

  • Meyer E. Dworsky, MD, Linda S. Reynolds, RN, BSN

  • Providence Alaska Medical Center, Anchorage, AK

  • Roy F. Davis, MD, Sharon J. Hulman, RN

  • Phoenix Children’s Hospital, Phoenix, AZ

  • Michael C. McQueen, MD

  • St Joseph’s Hospital & Medical Center, Phoenix, AZ

  • Montgomery Hart, MD, Marie King, RN

  • California Pacific Medical Center, San Francisco, CA

  • Terri A. Slagle, MD,

References (24)

  • CT Jones

    Reprogramming of metabolic development by restriction of fetal growth

    Biochem Soc Trans

    (1985)
  • JB Warshaw

    Intrauterine growth retardation: adaptation or pathology

    Pediatrics

    (1985)
  • Cited by (682)

    View all citing articles on Scopus

    Reprint requests: A. Lynn Stillman, Network Administrator, Vermont Oxford Network, 444 S Union St, Burlington, VT 05401.

    ☆☆

    0002-9378/2000 $12.00 + 06/1/101977

    View full text