Objectives: Magnesium sulfate (MgSO4) is among the most commonly used medications in labor and delivery units. It has been used as a mean to protect against eclampsia and a neuroprotective agent for fetuses at risk of preterm birth. In the present study we investigated its impact in the occurrence of postpartum uterine atony and hemorrhage.
Methods: We searched the Medline, Scopus, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL, Clinicaltrials.gov and Google Scholar databases for randomized trials and observational studies. Statistical analysis was performed with the Hartung-Knapp-Sidik-Jonkman model in RStudio using the meta package.
Results: Twelve studies fitted the predetermined criteria and these involved 41,190 women of whom 10,565 (25.6 %) received MgSO4. The meta-analysis revealed that the risk of postpartum uterine atony was similar among patients that received MgSO4 and those that did not (OR 1.93, 95 % CI 0.78, 4.81). Estimated blood loss (SMD 0.04, 95 % CI -0.10, 0.18) as well as the risk of postpartum hemorrhage (OR 1.82, 95 % CI 0.99, 3.35) also did not differ. Subgroup analysis revealed that evidence drawn from observational studies indicates a significant effect of MgSO4 on the odds of postpartum uterine atony and hemorrhage; however, randomized trials do not support this.
Conclusions: The results of our meta-analysis suggest that it is reasonable to consider MgSO4 in women at risk of delivering before the completion of its elimination half-life. However, physicians should be vigilant in cases at risk of postpartum hemorrhage as current data are very heterogeneous and should not be considered as definitive.
Keywords: Hemorrhage; Magnesium sulfate; Meta-analysis; MgSO(4); Neuroprotection; Preeclampsia; Uterine atony.
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