Maternal magnesium level effect on preterm labor treatment

To compare the initial serum magnesium levels between preterm labor (PL) and control groups and to evaluate MgSO4 treatment response in preterm labor group according to their initial serum magnesium levels.

Hundred women diagnosed as preterm labor between 28 and 33 weeks of gestation and 100 non-complicated pregnant women were enrolled in this prospective study. Total basal serum magnesium levels were measured in both the groups. After a 6 g intravenous bolus of MgSO4, a dose of 2 g/h was given as an infusion in the preterm labor group.

Serum magnesium levels were significantly lower in preterm labor group (p < 0.001). The active contractions stopped in 69 (73,4%) preterm patients. The basal Mg level was significantly lower in this preterm group (1.6 versus 1.9, respectively, p < 0.001). Predictive value of basal magnesium level measurement for magnesium tocolysis response was calculated by receiver operating characteristic analyses with 95% confidence interval. Positive predictive and negative predictive values were found as 64.5% and 92.5%, respectively, with 83% accuracy, when cut-off magnesium value was taken as a <1.75 mg/dl (sensitivity = 80%, specificity = 84,1%).

Basal magnesium levels in preterm labor had a predictive value in evaluating MgSO4 tocolysis response. It may help to select patients who are appropriate for MgSO4 tocolysis.