Seventy-two studies were included in the review (n= 5,672, range six to 975). Within these were 19 RCTs and 20 prospective and 19 retrospective cohort studies and one study of unknown design which reported on clinical outcomes in 63 distinct cohorts of women. The median quality score ranged from 5 to 6.5 out of 9 points. Thirteen studies examined prognostic factors.
In women with severe pre-eclampsia at less than 34 weeks, expectant care (39 cohorts, n=4,650) prolonged pregnancy by one to two weeks. Serious maternal complications were uncommon, apart from hypotension (upper limit 30%) and recurrent severe hypertension (upper limit 38%) associated with blood pressure management.
In women with HELLP, expectant care (12 cohorts, n=438) prolonged pregnancy by about five days. Severe complications were relatively common, especially recurrent severe hypertension. There were few data on maternal morbidity in interventionist cohorts for women with either severe pre-eclampsia or HELLP at less than 34 weeks. In women with severe pre-eclampsia at less than 28 weeks, expectant care (six cohorts, n=305) prolonged pregnancy by almost two weeks. Rates of maternal morbidity were similar in expectant and interventionist cohorts, although limited data suggested that rates of recurrent severe hypertension were more common with interventionist care.
No predictors of adverse outcomes were identified (13 studies).
Detailed results for these and other outcomes were reported in the review.