Sir.—Naeye et al1 have written an informative report on the 1955 to 1965 origins of cerebral palsy (CP) in America. However, I continue to marvel at how different groups have analyzed the same data from the Collaborative Perinatal Study (CPS), but with apparently different conclusions about the possible relationship of perinatal asphyxia and/or trauma tosubsequent neurological impairment.1,2
As one involved with the early CPS study at the University of Minnesota, Minneapolis, I know that, contrary to the authors' statements, pregnant patients routinely receive iron supplements. Indeed, during the time of the CPS study, we did not understand the normal "physiological anemia of pregnancy" and pregnant women who had a decline in their hemoglobin concentration despite oral iron therapy often received intravenous iron.
Furthermore, I believe obstetrical and neonatal advances have made the authors' observations, based on data collected 23 to 33 years ago, obsolete. Modern electronic fetal