Outborn status with a medical neonatal transport service and survival without disability at two years. A population-based cohort survey of newborns of less than 33 weeks of gestation.

Objective: Prenatal events are thought to play an important role in long-term handicap, but the specific role of perinatal factors remains controversial. Our study, conducted in the context of this debate, aimed to break down the various components of perinatal management and to assess the relationship between these components and survival without disability at the age of two years.

Study Design: A prospective geographically-defined study was conducted in 1985 in the Paris metropolitan area. It covered 53430 births (stillbirths and live births), including 539 that occurred between 25 and 32 weeks gestation. The relationship between perinatal management and survival without disability was studied by a multivariate analysis (logistic regression). The analysis was restricted to a group of 202 infants born at 31 or 32 week's gestation, to avoid indication bias.

Results: An inborn status (delivery in a tertiary care facility) exerted a protective effect on survival without disability at the age of two years (Adjusted Odds Ratio (OR)=7.51 [1.51; 37.4]), even though the area we studied possessed an excellent Medical Neonatal Transport Service. Multiple pregnancies also seemed to have a protective effect (Adjusted OR=2.45 [0.96; 6.27]). No statistically significant association was seen between survival without disability at two years and the presence of a hospital staff paediatrician in the delivery room.

Conclusion: These results lead us to consider what the concept of inborn/outborn represents in the perinatal management of infants at high risk.