Aim: To study whether breech presentation is a risk factor for cerebral palsy (CP).
Methods: Perinatal data from 177 272 children born in breech or vertex presentation in Norway during 1996 to 1998 were retrieved from the Medical Birth Registry of Norway. Data were collected between 1 January 2003 and 31 March 2006. Data on 245 children with CP were recorded in the Norwegian Cerebral Palsy Registry. Odds ratios (OR) with 95% confidence intervals (CI) for CP among children born in breech compared with vertex presentation were calculated. Confounding was addressed in logistic regression and stratified analyses.
Results: Among the 245 children with CP (46.5% females and 53.5% males), 31% had unilateral, 49% bilateral, 7% dyskinetic, and 5% the ataxic subtype, and 8% of cases were unclassified. Among children born in breech, the OR for CP was 3.6 (95% CI 2.4-5.3). The increased risk was reduced when adjusted for preterm birth, plurality, and smallness for gestational age. Among singletons born in breech by vaginal delivery at term, the OR for CP was 3.9 (95% CI 1.6-9.7). Severity or subtype of CP did not differ between breech and vertex presentation.
Interpretation: Breech delivery is a significant risk factor for CP, in particular among singletons born by vaginal delivery at term.