Recent published data suggest that antenatal exposure to magnesium therapy may be neuroprotective for VLBW infants, reducing the risk of cerebral palsy(Am J Obstet Gynecol 172:419, 1995) and IVH (J Child. Neurol. 7:70, 1992). We assessed and compared the frequency of IVH and of death for infants in the NICHD Neonatal Research Network (NRN) VLBW registry who were (n=1565) and were not (n=1038) exposed to antenatal magnesium. Data on maternal and infant conditions were obtained prospectively for VLBW infants (BW 401-1500 gnms) born 7/1/94 - 6/30/95 who were admitted to the 12 NRN centers. Multivariate analyses adjusting for birthweight, gestational age, race, gender, delivery mode, antenatal steroids, hypertension, and preeclampsia, were used to calculate the adjusted odds ratios (OR) for the effect of magnesium on mortality and IVH. Analyses were done for four groups: A- all VLBW infants; B- all ELBW infants 401-1000g; C- singleton birth VLBW infants without maternal diabetes, hypertension, eclampsia or preeclampsia; D- singleton birth ELBW infants without maternal diabetes, hypertension, eclampsia or preeclampsia A significant decrease in mortality rate was observed with magnesium exposure for the entire VLBW (A) and ELBW (B) populations. No statistically significant change in mortality was seen in either of the subgroups (C, D). An increased incidence of severe IVH was found in the singleton ELBW cohort (D). Whether magnesium itself, or other confounders (eg maternal indications for magnesium), account for the association of magnesium with varying neonatal outcomes remains uncertain. These data do not support the previously reported relationship between in utero magnesium exposure and reduction in IVH in the VLBW infant. Table

Table 1
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