Effects of suboptimal intra-uterine growth on preterm infants between 30 and 32 weeks' gestation.

Objective. To investigate the effects of suboptimal intra-uterine growth on the outcome of low-birth-weight (LBW) infants. Design. Prospective observational study. Setting. Neonatal unit of a tertiary care hospital. Patients. A total of 104 LBW infants with a gestation of 30 - 32 weeks were selected from a larger cohort that had previously been studied to ascertain the prevalence of respiratory distress syndrome (RDS) and periventricularintraventricular haemorrhage (PV-IVH). Outcome measures. Multivariate analysis was used to examine the association between RDS, PV-IVH and death, and the adequacy of intra-uterine growth. Results. Infants with a higher birth weight ratio or birthweight ≥ 25th percentile had an increased risk of developing RDS, particularly where ventilatory support was required. However, PV-IVH was associated with immediate perinatal events and not with intra-uterine growth. Mortality was not affected by intra-uterine growth, since those < 25th percentile, in spite of being at lower risk for RDS, showed a trend towards more infection-related deaths. Conclusions. The 'intra-uterine stress' experienced by infants with suboptimal intra-uterine growth appears to protect partially against RDS, but confers no overall advantage in terms of survival.