To the Editor.
—In their Letter, Dr Allred and colleagues1 raise important methodologic considerations about the association between maternal treatment with magnesium sulfate and reduced risk of cerebral palsy (CP) in very low-birthweight children reported by Schendel et al2 and previously by us3 for a cohort of children in northern California. Perhaps in Boston, Mass, magnesium first was used for tocolysis only after 1988, but that does not appear to be true in our study of the California cohort of children born in 1983 through 1985. Medical records for these births clearly indicate that magnesium was used for tocolysis in preterm labor in 57% of those who received magnesium.We classified women in our study according to whether a clinical diagnosis of preeclampsia was reported in their medical records. In addition, we searched all medical records of patients who were admitted for delivery for evidence of blood
Nelson KB, Grether JK. More on Prenatal Magnesium Sulfate and Risk of Cerebral Palsy. JAMA. 1997;278(18):1493. doi:10.1001/jama.1997.03550180043030