Objective: to determine the perinatal risk factors of neurodevelopmental disabilities of very preterm birth applying logistic regression analysis.

Design: prospective, geographically-defined collaborative study in the region of Franche-Comtè(France).

Subjects: perinatal and follow-up data were collected on 203 consecutive liveborn singleton or twin non malformed infants with gestational age less than 33 weeks from 10/01/90 to 09/30/92.

Main outcome measure: rate of cerebral palsy and severe mental retardation determined by family-physician or pediatrician with a screening-skill test performed at two years of age.

Results: 167/171 (98%) survivors were evaluated. Twenty-two of the 167 examined infants (13.2%) showed signs of cerebral palsy, 10 of these showed a severe cerebral palsy or mental retardation. Risk factors of disabilities are in a multivariate approach: premature rupture of membranes>=48h (OR: 4.3, 95% confidence interval 1.6-11.8), monochorionic-twin placentation (OR: 6.0, 95% CI 1.7-21.3), respiratory distress syndrome (OR: 2.8, 95% CI 1.1-7.1).

Conclusion: this geographically-defined prospective study gives epidemiological data and strongly suggests that a link does exist between prenatal events (monochorionic-twin placentation, premature rupture of membranes), post-natal event (respiratory distress syndrome) and neurological disabilities of ancient preterm infants.