The prevalence of cerebral palsy (CP) in children born at 20 to 27 weeks of age and weighing 500 to 1,249 g has steadily declined in the last 10 or so years, reversing a trend of growing prevalence leading up to 1992–1994 (the peak period for CP), according to a Canadian study.
The analysis, involving 2,318 infants born very prematurely between 1974 and 2003, is important because a decrease in prevalence suggests successful prevention of CP through improved perinatal care.
Experts are unsure as to the cause of the decrease. Available evidence fails to support the belief that the drop resulted from the use of antenatal steroids, magnesium sulfate, thyroid hormone, surfactant, vitamin K, or phenobarbital. However, it may be the result of a number of changes in care, such as less use of postnatal corticosteroids.
Robertson CM, Watt MJ, Yasui Y. Changes in the prevalence of cerebral palsy for children born very prematurely within a population-based program over 30 years. JAMA. 2007;297:2733-2740.