Association between Maternal Body Mass Index and Sub-therapeutic Serum Magnesium Level in Severe Preeclampsia at Maharat Nakhon Ratchasima Hospital

Objectives: To evaluate association between the maternal body mass index (BMI) and subtherapeutic serum magnesium level in pregnant women with severe preeclampsia who received magnesium sulfate therapy at Maharat Nakhon Ratchasima Hospital. Study design: Retrospective cross-sectional study. Materials and Methods:  A retrospective study from October 1, 2012 to March 31, 2015 was performed to estimate the effect of maternal BMI on serum magnesium level. And 565(2.99 %) pregnant women had severe preeclampsia and eclampsia diagnosed and received magnesium sulfate therapy at Maharat Nakhon Ratchasima Hospital. Inclusion criteria was pregnant women delivered at gestational age ≥ 24 weeks, not expectant management, received magnesium sulfate in regimen loading dose 4 grams, followed by maintenance dose 1 gram/hour intravenously, and monitored serum magnesium level. Serum magnesium level was monitored initially at 3-4 hours after loading dose, and then monitored every 4 hours during magnesium sulfate infusion. The first serum magnesium level after loading dose was used in the study. Association between maternal BMI and subtherapeutic serum magnesium level (magnesium level 1.1 gm/dL) and thrombocytopenia seem to have higher rate of therapeutic magnesium level significantly (P value < 0.05). Conclusion: Most cases of women with severe preeclampsia at Maharat Nakhon Ratchasima Hospital had subtherapeutic serum magnesium level when magnesium sulfate was administered in regimen loading dose 4 grams, followed by 1 gram per hour intravenously. Overweight and obesity were high risk factor contributing to subtherapeutic of serum magnesium level.