Objectives To estimate the national incidence of eclampsia in the UK and to describe the management and associated outcomes since the introduction of magnesium sulphate.
Design A population-based descriptive study using the newly established UK Obstetric Surveillance System (UKOSS).
Setting All 229 hospitals with consultant-led maternity units in the UK.
Population All women in the UK delivering between February 2005 and February 2006.
Methods Prospective case identification through the monthly mailing of UKOSS.
Main outcome measures Incidence and mortality rates with 95% confidence intervals.
Results Data collection was complete for 94% of women. The incidence of eclampsia was 2.7 cases per 10 000 births (95% CI 2.4–3.1). Thirty-eight percent of women had established hypertension and proteinuria in the week before their first fit. Ninety-nine percent of women were treated with magnesium sulphate. No women in the study died. Fifty-four women (26%) had recurrent fits. One hundred and nineteen women (56%) were admitted to intensive care or obstetric high dependency units for a median of 2 days (range 1–9). Twenty-two women (10%) were reported to have other severe morbidity after the eclamptic episode. Outcomes were known for 222 infants (204 singletons and 18 twins). Eight infants were stillborn and five died in the neonatal period (perinatal mortality 59/1000 births [95% CI 32–98]).
Conclusions The incidence of eclampsia and its complications have decreased significantly in the UK since 1992, following the introduction of management guidelines for eclampsia and pre-eclampsia. These results are consistent with the findings of the randomised controlled trials of magnesium sulphate. This study has shown the practical benefits of the incorporation of research evidence into practice.