Objective: To determine the influence of intrauterine growth retardation of preterm infants on mortality and cognitive development.
Design: A nationwide study cohort of very preterm and/or small for gestational age infants (< 32 weeks and/or < 1500 g) born alive in 1983 in the Netherlands. Assessment on neuromotor and cognitive development at five years, and a parental questionnaire on school performance at nine years. Cognitive outcome is defined as handicap for mental and speech-language development, and need for special education.
Sample: 134 small for gestational age infants (< 10th centile) and 410 appropriate for gestational age infants (between 25th and 75th centile) of all infants between 25 and 32 weeks of gestational age were identified; infants with congenital malformations and not of caucasian race were excluded.
Main outcome measures: Neonatal mortality, in-hospital and five years mortality; Cognitive outcome at five years; School performance at nine years.
Results: The mortality risk for small for gestational age compared with appropriate for gestational age infants was significantly higher, after adjustment for gestational age, sex, multiple pregnancy and mode of delivery (OR 2.56, 95% CI 1.26-5.26). Small for gestational age infants showed more often gross motor and minor neurological dysfunction, but less cerebral palsy than appropriate for gestational age infants. Cognitive outcome at five years in small for gestational age infants was significantly worse than appropriate for gestational age infants stratified for mode of delivery OR 2.44 (95% CI 1.05-5.55). At nine years of age significantly more small for gestational age infants (16.4%) needed special education than appropriate for gestational age infants (11.9%).
Conclusion: Intrauterine growth retardation increases the risk of mortality and of cognitive disorders.