Eclampsia in Southern Alberta: is there a role for seizure prophylaxis in all women with gestational hypertension?

OBJECTIVE: To evaluate the predictability of eclampsia and explore the role for seizure prophylaxis in a population with a low frequency of seizure prophylaxis.

METHODS: A retrospective review was conducted of all women with eclampsia registered at the Foothills Hospital in Calgary, Alberta, between 1991 and 2000. The data collected included timing of seizure in relation to diagnosis of gestational hypertension (GHTN) and delivery, method of seizure prophylaxis (if any), and maternal characteristics.

RESULTS: During the study period, 3075 of 38,577 women (8.0%) were diagnosed with GHTN, with or without proteinuria or adverse conditions. Three percent had received magnesium sulfate for seizure prophylaxis. Of these 3075 women, 17 (0.6%) developed eclampsia, none of whom was receiving magnesium sulfate for seizure prophylaxis at the time. Of these, 10 women (59%) exhibited GHTN prior to their first seizure, including 6 women with GHTN with adverse conditions, 3 with GHTN with proteinuria but without adverse conditions, and 1 with GHTN without proteinuria or adverse conditions. Five of the 17 women had seizures that occurred prior to labour, 6 were intrapartum, and 6 were postpartum. Nine (53%) of the 17 women with eclampsia had their initial seizure after the diagnosis of GHTN and before 24 hours postpartum.

CONCLUSION: Seizure prophylaxis for all the women with GHTN, from the time of diagnosis through 24 hours postpartum, may have been able to prevent as many as 53% of eclamptic episodes. Three hundred and seven women with GTHN would have to receive seizure prophylaxis to prevent one seizure.