A baby who is born prematurely usually has a low birth weight, less than 5.5 lb (2.5 kg). But full-term babies can also have low birth weights. Multiple-birth babies are more likely than single-birth babies to be born early or with a low birth weight.
Most children with CP had a disruption in the normal development of parts of their brain during fetal growth. Low-birth-weight, premature babies are more likely than full-term, normal-weight babies to have had developmental problems during fetal growth that can injure the brain. For example, a condition called periventricular leukomalacia, or PVL, which reflects injury to the white matter of the brain, is more likely in babies born prematurely than in those born at full term.