Abstract: We included one small study (involving 24 women). The study was a single-centre randomised trial conducted in Mexico. This study compared a control group who received antihypertensive therapy, anticonvulsant therapy, plasma expanders, corticosteroids and dypyridamole with an intervention group that received epidural block instead of the antihypertensives, as well as all the other four drugs. Lumbar epidural block was given using 0.25% bupivacaine, 10 mg bolus and 5 mg each hour on continuous epidural infusion for six hours. This study was at low risk of bias in three domains but was assessed to be high risk of bias in two domains due to lack of allocation concealment and blinding of women and staff, and unclear for random sequence generation and outcome assessor blinding. The included study did not report on any of this review's important outcomes. Meta-analysis was not possible. For the mother, these were: maternal death (death during pregnancy or up to 42 days after the end of the pregnancy, or death more than 42 days after the end of the pregnancy); development of eclampsia or recurrence of seizures; stroke; any serious morbidity: defined as at least one of stroke, kidney failure, liver failure, HELLP syndrome (haemolysis, elevated liver enzymes and low platelets), disseminated intravascular coagulation, pulmonary oedema. For the baby, these were: death: stillbirths (death in utero at or after 20 weeks' gestation), perinatal deaths (stillbirths plus deaths in the first week of life), death before discharge from the hospital, neonatal deaths (death within the first 28 days after birth), deaths after the first 28 days; preterm birth (defined as the birth before 37 completed weeks' gestation); and side effects of the intervention. Reported outcomes The included study only reported on a single secondary outcome of interest to this review: the Apgar score of the baby at birth and after five minutes and there was no clear difference between the intervention and control groups. The included study also reported a reduction in maternal diastolic arterial pressure. However, the change in maternal mean arterial pressure and systolic arterial pressure, which were the other reported outcomes of this trial, were not significantly different between the two groups. Currently, there is insufficient evidence from randomised controlled trials to evaluate the effectiveness, safety or cost of using epidural therapy for treating severe pre-eclampsia in non-labouring women. High-quality randomised controlled trials are needed to evaluate the use of epidural agents as therapy for treatment of severe pre-eclampsia. The rationale for the use of epidural is well-founded. However there is insufficient evidence from randomised controlled trials to show that the effect of epidural translates into improved maternal and fetal outcomes. Thus, there is a need for larger, well-designed studies to come to an evidence-based conclusion as to whether the lowering of vasomotor tone by epidural therapy results in better maternal and fetal outcomes and for how long that could be maintained. Another important question that needs to be answered is how long should extended epidural be used to ensure any potential clinical benefits and what could be the associated side effects and costs. Interactions with other modalities of treatment and women's satisfaction could represent other avenues of research.

Plain-language summary: We searched for evidence in July 2017 and identified one small randomised controlled study (involving 24 women) for inclusion in this review. The women were at 30 weeks of gestation or more, diagnosed with severe pre-eclampsia, and being cared for in an intensive care unit. They were randomly assigned to an epidural block plus their other medications or a drug to treat their high blood pressure plus their other medications. After six hours of treatment they all underwent a caesarean section. The included study did not report on any of the important outcomes of interest in this review such as death of the mother, death of her baby (before or after being born), serious illness for the mother or her baby, the mother developing eclampsia or seizures, or side effects of the intervention. The study authors did report difference in the infant Apgar scores between the two groups The study authors also reported a clear drop in the diastolic blood pressure in the epidural group compared to the other group. Systolic and mean blood pressures were similar in the two groups of women. However, the study did not report on any other mother or baby outcomes of interest in this review. There is not enough evidence from randomised controlled trials to evaluate the use of epidural therapy in severe pre-eclampsia to improve outcomes for the mother or her baby. High-quality trials are needed to evaluate the efficacy, safety and cost of epidural therapy in severe pre-eclampsia. Future studies could report on important outcomes such as those listed in this review.