PP163. Are we using magnesium sulphate excessively for preeclamptic patients?

There is now evidence that magnesium sulfate can prevent and control eclamptic seizures. For women with pre-eclampsia, magnesium sulfate reduces by more than one half the risk of eclampsia. After Magpie Trial [1] our clinical practice has been modified in terms of more liberal use of MgSO4, but the evidence regarding the benefit-to-risk ratio of MgSO4 prophylaxis in mild preeclampsia remains uncertain [2]. Thus we consider important to evaluate whether there are specific characteristics between patients who received the medicine that might signal risk and justify our decisions.

To identify in a group of hypertensive patients who used magnesium sulfate, clinical and/or laboratory characteristics that can be defined as specific risk factors and be useful to base clinical decisions.

The study was conducted at the Maternity School of Vila Nova Cachoeirinha, a public institution located in the north of the city of São Paulo (Baazil) between 01/07 and 31/12/2011. This is a retrospective study of a series of 103 pregnant women with hypertensive disorders, defined according to NHBPEP. We excluded patients admitted in labor. Patients were assigned into two groups according to the use of MgSO4. We compared clinical and laboratory characteristics between the two groups.

Of 103 patients included, 31 (30.1%) received MgSO4. Among the outcomes analyzed, there were significant differences in the group that received MgSO4 in terms of blood pressure equal to or greater than 110mmHg, clinical symptoms (eg headache and visual disturbance) and at least some evidence of organ dysfunction (hepatic, renal, haematologic, or central nervous system) (Table 1). Table 1. Variables associated with theuse of magnesium sulfate.

We can say that in our institution over the years was an increase in the use of magnesium sulfate. Our results support the hypothesis that about one in three patients treated at this institution receive the medication. Although our protocol admits that the decision may be based on subjective criteria, we identified some objective characteristics that supported their application, and that these criteria do not differ from the classic recommendations. We can also conclude that in our clinical experience we do not have identified a clear justification for support the routinely use of magnesium sulphate for all women with preeclampsia.