Characteristics of unilateral cerebral palsy according to gestational age at birth: A retrospective study

AIM: To investigate the relationship between gestational age and clinical and magnetic resonance imaging (MRI) characteristics in infants with unilateral cerebral palsy (CP). METHOD: This was a retrospective study of infants with unilateral CP in the Canadian CP Registry. Gestational age was considered as continuous and categorical. Neonatal signs were encephalopathy or seizures. M patterns were focal, white matter injury (WMI), and other. Additional impairments included seizures and non-motor-related impairments. The relationships between gestational age, imaging, and impairments were evaluated using multivariable and multinomial regression. RESULTS: There were 826 participants: 572 (69.3%) were born at term (>36.9 weeks), 121 (14.6%) were born moderate-to-late preterm (32-36.9 weeks), and 133 (16.1%) were born very-to-extremely preterm (< 32 weeks). Neonatal clinical signs (encephalopathy, seizures) were less common in infants born from 32 to 36.9 weeks (odds ratio [OR] = 0.24, 95% confidence interval [CI] = 0.10-0.57) than infants born at term. Common MRI patterns were focal injury in 417 (68.2%) and WMI in 68 (11.1%). Focal injury increased with gestational age (OR = 1.06, 95% CI = 1.02-1.1), while WMI decreased (OR = 0.88, 95% CI = 0.83-0.93). Impairments did not vary with gestational age but were associated with specific MRI patterns. INTERPRETATION: Most children with unilateral CP are born at term without neonatal signs of neurological injury. Gestational age at delivery was associated with neonatal signs and MRI pattern but not development of specific severe impairments.