Prematurity represents an independent risk factor for eclampsia in preeclamptic women being treated with MgSO4

Abstract

PREECLAMPTIC WOMEN BEING TREATED WITH MGSO4. MICHAEL BELFORT, JOHN ANTHONY, GEORGE SAADE, STEVEN CLARK, GARY DILDY, JANALEE THOMPSON, University of Utah, Obstetrics and Gynecology, Salt Lake City, Utah, University of Cape Town, Obstetrics and Gynaecology, Cape Town, South Africa, University of Texas Medical Branch at Galveston, Obstetrics & Gynecology, Galveston, Texas, University of Utah, Salt Lake City, Utah, Louisiana State University Medical Center at New Orleans, Obstetrics & Gynecology, Salt Lake City, Utah, St. Mark’s Hospital, Hospital Corporation of America, Maternal-Fetal Medicine, Salt Lake City, Utah OBJECTIVE: Magnesium sulfate (MgSO4) has an approximately 1% seizure prophylaxis failure rate in preeclampsia. Currently, factors predictive of seizure in such patients are unclear. STUDY DESIGN: Prospective data from preeclamptic women randomized to MgSO4 therapy were analyzed with univariate and multiple logistic regression analysis to determine independent variables associated with intrapartum and postpartum seizures. Variables included maternal age, race, gestational age, gravidity, previous preeclampsia, diabetes, chronic hypertension, epigastric pain, scotomata, headache, systolic BP, diastolic BP, platelet count, AST, ALT, and serum creatinine. A p ! 0.05 was used to denote statistical significance. RESULTS: 2038 patients were enrolled in two separate studies, of which 921 patients were randomized to MgSO4. Nine women or 0.98%, (95 percent confidence limits = 0.45% to 1.85%) on MgSO4 experienced seizure prophylaxis failure (8 intrapartum and 1 postpartum). No eclamptic patient had intracranial hemorrhage or other significant long-term neuropathology diagnosed and all recovered completely. By univariate analysis, lower gestational age and lower platelet count were identified as predictors of MgSO4 prophylaxis failure. On the multivariate regression analysis, only gestational age remained significantly associated with eclampsia (p = 0.04). 89% of patients in the seizure group (8/9) were !37 weeks while 61% (559/912) were preterm in the non-seizure group. CONCLUSION: Preterm preeclamptic patients (8/559 = 1.43%) receiving MgSO4 eclampsia prophylaxis are more likely to convulse than term patients (1/362 = 0.27%).