Incidence of breakthrough eclampsia and associated factors among women with severe pre-eclampsia receiving the zuspan regimen of magnesium sulfate: A prospective study

Background: Severe pre-eclampsia is a leading cause of maternal and perinatal morbidity and mortality. Although magnesium sulfate is a standard anticonvulsant for seizure prophylaxis, some patients still progress to eclampsia. Aims and Objectives: This study determined the incidence of breakthrough eclampsia and evaluated the factors associated with its occurrence in women receiving the Zuspan regimen. Materials and Methods: A prospective observational study was conducted over a period of 1 year, from February 2021 to January 2022, among 224 patients with severe pre-eclampsia admitted to the Labour and Delivery Unit, IOG and ISO-KGH, Chennai. Following ethical approval and informed consent, all patients received a Zuspan regimen of magnesium sulfate and were monitored throughout their hospital stay. Demographic, obstetric, maternal, and neonatal data were recorded until delivery, and progression to eclampsia was assessed. Results: Of the 224 patients, 14 (6.3%) developed eclampsia, whereas 210 (93.8%) remained seizure-free. The mean age and body mass index (BMI) were 27.29±5.60 years and 30.11±3.77 kg/m2, respectively. Rural residence, gestational age >36 weeks, and mild anemia were observed in 45.5%, 56.7%, and 80.4% of patients. Hypothyroidism and gestational diabetes mellitus (GDM) were present in 31.3% and 10.3%, respectively. Eclampsia was significantly associated with GDM (P=0.01), fetal growth restriction (P=0.03), end-organ damage (P=0.01), neonatal intensive care unit admission (P=0.001), and obstetric score (P=0.044), but not with age, BMI, anemia, residence, hypothyroidism, or mode of delivery. Conclusion: Most women with severe pre-eclampsia remained seizure-free during Zuspan magnesium sulfate prophylaxis, although 6.3% developed breakthrough eclampsia. Early recognition of high-risk features and careful clinical monitoring may further reduce breakthrough seizures and improve maternal and neonatal outcomes.