Second overview of relationships between antenatal pharmacologic magnesium sulfate and neurologic outcomes in children.

In the last ten years, the body of scientific knowledge concerning the use of antenatal pharmacologic magnesium sulfate (MgSO4) has become substantially larger. Several randomized controlled trials have provided compelling evidence that MgSO4 is the drug of choice for maternal seizure prophylaxis in toxemia. In contrast, the recent Cochrane Systematic Review, as well as other studies, have shown there is no evidence basis for the use of MgSO4 for tocolysis. Furthermore, when tocolytic-strength doses of MgSO4 are employed, there is an excess risk for total pediatric mortality (Cochrane Systematic Review and our own previous work). It is conceivable, nonetheless, that low doses of MgSO4, when used as prophylaxis in some selected cases of preterm labor, may ultimately be shown to be neuroprotective for a relatively small number of children. Unfortunately, the indiscriminate use of high-dosage MgSO4 for attempted tocolysis in preterm labor is much more likely to cause harm than do good.