Survival of very-low-birth-weight infants according to birth weight and gestational age in a public hospital

Abstract

Objectives: To determine the survival rates for infants weighing 500 - 1 499 g according to birth weight (BW) and gestational age (GA).

Design: This was a retrospective cohort study. Pregnancy and delivery data were collected soon after birth and neonatal data at discharge or at death.

Setting: Chris Hani Baragwanath Hospital (CHBH), a public-sector referral hospital, affiliated to the University of the Witwatersrand.

Subjects: Live births weighing between 500 g and 1 499 g delivered at or admitted to CHBH from January 2000 to December 2002.

Outcome measures: BW and GA-specific survival rates for all live infants born at CHBH and for those admitted for neonatal care.

Results: Seventy-two per cent of infants survived until discharge. The survival to discharge rate was 32% for infants weighing < 1 000 g, and 84% for those weighing 1 000 - 1 499 g. Survival rates at 26, 27 and 28 weeks' gestation were 38%, 50% and 65% respectively. Survival rates for infants admitted to the neonatal unit were better than rates for all live births, especially among those weighing < 1 000 g or with a GA < 28 weeks. There was a marked increase in survival between the 900 - 999 g and 1 000 - 1 099 g weight groups. Provision of antenatal care, caesarean section, female gender and an Apgar score more than 5 at 1 or 5 minutes were associated with better survival to hospital discharge.

Conclusion: Survival among infants weighing less than 1 000 g is poor. In addition to severe prematurity, the poor survival among these infants (< 1 000 g) is most likely related to the fact that they were not offered mechanical ventilation. Mechanical ventilation should be offered to infants weighing < 1 000 g as it may improve their survival even in institutions with limited resources.