Changes in survival and neonatal morbidity in infants with a birth weight of 750 g or less.

BACKGROUND

Improvement in perinatal and neonatal care has resulted in increased survival of extremely low birth weight (ELBW) infants.

OBJECTIVES

To describe survival and neonatal morbidity in a cohort of ELBW infants, to compare two consecutive 5-year periods, and compare appropriate (AGA) with small for gestational age (SGA) infants (AGA ≥p10, and SGA <p10).

METHODS

Retrospective cohort study of 179 live-born infants with a birth weight (BW) of ≤750 g and gestation of ≥24 weeks, born in 1996-2000 (cohort I, n = 94) and 2001-2005 (cohort II, n = 85) in the Wilhelmina Children's Hospital Utrecht, the Netherlands.

RESULTS

During NICU stay (n = 146) 62.3% experienced infant respiratory distress syndrome (IRDS), 46.6% bronchopulmonary dysplasia, 50.7% septicemia, 34.2% periventricular leukomalacia grade I and 24.7% intraventricular hemorrhage grade I/II. IRDS grade III/IV occurred significantly more often in cohort I (p = 0.042), whereas septicemia and hyperbilirubinemia occurred more in cohort II (p = 0.045 and p = 0.001). In AGA infants mean gestation was significantly shorter (p < 0.001), and IRDS grade III/IV (p = 0.015), mechanical ventilation (p = 0.045) and patent ductus arteriosus (p = 0.003) were significantly more prevalent. Overall survival was 62%, and survival in the NICU increased from 65.8% (cohort I) to 88.1% (cohort II, p = 0.002). Survival of AGA and SGA infants did not differ, but increased with time (71.4 to 75.9% and 61.4 to 97.4%, respectively).

CONCLUSIONS

Mortality of infants with a BW of ≤750 g is high, but decreased over time, especially in SGA infants. Considerable neonatal morbidity was present, especially in AGA infants, most likely due to their significantly shorter gestation.