Cerebral palsy and newborn care. I: secular trends in cerebral palsy.

Reports of cerebral palsy prevalence rates per live births in recent decades in western nations show a mixed pattern. Declining rates were noted in Bristol, England, and in Denmark; but more recently a rising rate was noted in Ireland. In Western Sweden a decline has been followed by a recent rise, and in Western Australia a rise has been followed by a decline. Rates with not statistically significant changes have been found in Iceland and Birmingham, England, and over the seven-year span of the US Collaborative Perinatal Project, although their over-all direction was downward. No single factor is likely to explain the trends observed.