Cerebral hemodynamics in preeclampsia: cerebral perfusion and the rationale for an alternative to magnesium sulfate

Obstet Gynecol Surv. 2006 Oct;61(10):655-65. doi: 10.1097/01.ogx.0000238670.29492.84.


Preeclampsia and eclampsia continue to be major causes of maternal death. Currently, approximately 18% of U.S. maternal deaths are attributed to hypertensive disorders and eclampsia, and several hundred women die from eclampsia and its complications every year. In the United States, preeclamptic women have received magnesium sulfate as a seizure prophylaxis agent for 3 decades, and this practice is becoming more widely accepted internationally. In addition to a recognized failure rate, there are financial, logistic, and safety concerns associated with the universal administration of magnesium sulfate. Many institutions in the developing world lack the necessary equipment and expertise to administer the medication, and many preeclamptic patients thus do not receive magnesium sulfate before their first seizure. As effective as it has been in reducing mortality from eclampsia, magnesium sulfate is also associated with appreciable morbidity and mortality from administration errors and magnesium toxicity. The availability of an easily administered, cheap, safe, and orally administered alternative to magnesium sulfate would be welcomed in the developing world and would provide an extremely useful alternative therapy to the current standard of care. Recent advances in the understanding of the pathophysiology of preeclampsia and eclampsia, primarily related to cerebral perfusion and blood flow, could allow us to reduce the seizure rate in treated preeclamptic women even further than what is currently reported. This article deals with the rationale behind the use of labetalol as an alternative to magnesium sulfate for the prevention of eclampsia.

Target audience: Obstetricians & Gynecologists, Family Physicians.

Learning objectives: After completion of this article, the reader should be able to recall that hypertensive diseases of pregnancy contribute a significant portion of today's maternal mortality, explain that methods of preventing eclampsia are not applicable worldwide, and state that understanding of the pathophysiology of preeclampsia/eclampsia may assist in developing safe and effective medications that can be used universally.

Publication types

  • Review

MeSH terms

  • Anticonvulsants / administration & dosage
  • Anticonvulsants / adverse effects
  • Anticonvulsants / therapeutic use*
  • Antihypertensive Agents / therapeutic use
  • Cerebrovascular Circulation / drug effects*
  • Eclampsia / physiopathology
  • Eclampsia / prevention & control
  • Female
  • Humans
  • Labetalol / administration & dosage
  • Labetalol / adverse effects
  • Labetalol / therapeutic use*
  • Magnesium Sulfate / administration & dosage
  • Magnesium Sulfate / adverse effects
  • Magnesium Sulfate / therapeutic use*
  • Multicenter Studies as Topic
  • Pre-Eclampsia / drug therapy*
  • Pre-Eclampsia / physiopathology*
  • Pregnancy
  • Pregnancy Complications, Cardiovascular / drug therapy
  • Pregnancy Complications, Cardiovascular / physiopathology
  • Pulsatile Flow / drug effects
  • Randomized Controlled Trials as Topic
  • Research Design
  • United States / epidemiology


  • Anticonvulsants
  • Antihypertensive Agents
  • Magnesium Sulfate
  • Labetalol