Magnesium for seizure prophylaxis in patients with mild preeclampsia

Hypertensive Disorders of Pregnancy

Hypertensive disorders in pregnancy are a leading cause of global maternal and fetal morbidity. The four hypertensive disorders of pregnancy include chronic hypertension, gestational hypertension, preeclampsia-eclampsia, and chronic hypertension with superimposed preeclampsia. A careful history, review of systems, physical examination, and laboratory analysis can help differentiate these disorders and quantify the severity of the disease, which holds important implications for disease management. This article reviews the different types of disorders of hypertension in pregnancy and how to diagnose and manage these patients, with special attention paid to any recent changes made to this management algorithm.

Eclampsia in the 21st century

The reported incidence of eclampsia is 1.6 to 10 per 10,000 deliveries in developed countries, whereas it is 50 to 151 per 10,000 deliveries in developing countries. In addition, low-resource countries have substantially higher rates of maternal and perinatal mortalities and morbidities. This disparity in incidence and pregnancy outcomes may be related to universal access to prenatal care, early detection of preeclampsia, timely delivery, and availability of healthcare resources in developed countries compared to developing countries. Because of its infrequency in developed countries, many obstetrical providers and maternity units have minimal to no experience in the acute management of eclampsia and its complications. Therefore, clear protocols for prevention of eclampsia in those with severe preeclampsia and acute treatment of eclamptic seizures at all levels of healthcare are required for better maternal and neonatal outcomes. Eclamptic seizure will occur in 2% of women with preeclampsia with severe features who are not receiving magnesium sulfate and in <0.6% in those receiving magnesium sulfate. The pathogenesis of an eclamptic seizure is not well understood; however, the blood-brain barrier disruption with the passage of fluid, ions, and plasma protein into the brain parenchyma remains the leading theory. New data suggest that blood-brain barrier permeability may increase by circulating factors found in preeclamptic women plasma, such as vascular endothelial growth factor and placental growth factor. The management of an eclamptic seizure will include supportive care to prevent serious maternal injury, magnesium sulfate for prevention of recurrent seizures, and promoting delivery. Although routine imagining following an eclamptic seizure is not recommended, the classic finding is referred to as the posterior reversible encephalopathy syndrome. Most patients with posterior reversible encephalopathy syndrome will show complete resolution of the imaging finding within 1 to 2 weeks, but routine imaging follow-up is unnecessary unless there are findings of intracranial hemorrhage, infraction, or ongoing neurologic deficit. Eclampsia is associated with increased risk of maternal mortality and morbidity, such as placental abruption, disseminated intravascular coagulation, pulmonary edema, aspiration pneumonia, cardiopulmonary arrest, and acute renal failure. Furthermore, a history of eclamptic seizures may be related to long-term cardiovascular risk and cognitive difficulties related to memory and concentration years after the index pregnancy. Finally, limited data suggest that placental growth factor levels in women with preeclampsia are superior to clinical markers in prediction of adverse pregnancy outcomes. This data may be extrapolated to the prediction of eclampsia in future studies. This summary of available evidence provides data and expert opinion on possible pathogenesis of eclampsia, imaging findings, differential diagnosis, and stepwise approach regarding the management of eclampsia before delivery and after delivery as well as current recommendations for the prevention of eclamptic seizures in women with preeclampsia.

Hypertensive Disorders of Pregnancy

"Pregnancy-induced hypertension" (HDP) describes a spectrum of disorders, including gestational hypertension, preeclampsia, and chronic hypertension with superimposed preeclampsia. Each of these disease processes can progress to a more pathologic case with worsening hypertensive disease, end-organ damage, and concerning clinical sequelae. Risk factors for HDP include nulliparity, a prior pregnancy complicated by hypertension, and obesity. Close blood pressure monitoring, serologic and urine testing, and prompt clinical follow-up remain the gold standard for antenatal diagnosis and surveillance. Optimizing maternal and neonatal outcomes involves early prenatal diagnosis, a multidisciplinary team-based approach, and referral to an experienced provider for cases with advanced pathology.

Practice Modification for Pandemics: A Model for Surge Planning in Obstetrics

This review highlights proposed pandemic-adjusted modifications in obstetric care, with discussion of risks and benefits based on available evidence. We suggest best practices for balancing community-mitigation efforts with appropriate care of obstetric patients.

ACOG Practice Bulletin No. 202: Gestational Hypertension and Preeclampsia

Hypertensive disorders of pregnancy constitute one of the leading causes of maternal and perinatal mortality worldwide. It has been estimated that preeclampsia complicates 2-8% of pregnancies globally (). In Latin America and the Caribbean, hypertensive disorders are responsible for almost 26% of maternal deaths, whereas in Africa and Asia they contribute to 9% of deaths. Although maternal mortality is much lower in high-income countries than in developing countries, 16% of maternal deaths can be attributed to hypertensive disorders (). In the United States, the rate of preeclampsia increased by 25% between 1987 and 2004 (). Moreover, in comparison with women giving birth in 1980, those giving birth in 2003 were at 6.7-fold increased risk of severe preeclampsia (). This complication is costly: one study reported that in 2012 in the United States, the estimated cost of preeclampsia within the first 12 months of delivery was $2.18 billion ($1.03 billion for women and $1.15 billion for infants), which was disproportionately borne by premature births (). This Practice Bulletin will provide guidelines for the diagnosis and management of gestational hypertension and preeclampsia.

Hypertensive Disorders in Pregnancy

Hypertensive disorders of pregnancy are a heterogeneous group of conditions that include chronic hypertension, gestational hypertension, preeclampsia, and preeclampsia superimposed on chronic hypertension. These disorders account for a significant proportion of perinatal morbidity and mortality nearly 10% of all maternal deaths in the United States. Given the substantial health burden of hypertensive disorders in pregnancy, there is increasing interest in optimizing management of these conditions. This article summarizes the diagnosis and management of each of the disorders in the spectrum of hypertension in pregnancy and highlights recent updates in the field.

Preeclampsia: Short-term and Long-term Implications

Preeclampsia is a hypertensive disorder that affects 4% of pregnancies and has a high risk of maternal, fetal, and neonatal morbidity and mortality, as well as long-term cardiovascular risk. Recent updates in the definition, diagnosis, and management guidelines for preeclampsia warrant review by general obstetrician-gynecologists. Screening and prevention algorithms for preeclampsia are available, but ultimately the cure remains delivery of the fetus and placenta. Close monitoring for the development and worsening of preeclampsia during pregnancy is essential to optimize both maternal and fetal/neonatal outcomes.

Preterm preeclampsia: 32 to 37 weeks gestation

OBJECTIVE

To evaluate neonatal outcomes in late preterm infants delivered due to preeclampsia.

METHODS

A retrospective cohort of 3580 infants delivered at 32 0/7 to 36 6/7 weeks gestation was examined. Neonatal outcomes of infants delivered due to preeclampsia were compared with outcomes of infants delivered prematurely due to other etiologies. Multivariate logistic regression was used to analyze the association between preeclampsia and the neonatal outcomes.

RESULTS

Infants of women with preeclampsia were more likely to be SGA (26.8% vs. 8.4%). They were also more likely to be admitted to the ICN (54.3% versus 39.0%); however, they were less likely to suffer a neonatal death (2.2% vs. 3.4%). Infants born to women with preeclampsia had similar rates of RDS (19.8% vs. 14.2%).

DISCUSSION

Neonatal outcomes in late preterm infants born to preeclamptic mothers are significantly different from outcomes in late preterm neonates delivered due to other indications.

Magnesium sulfate: past, present, and future

First used anecdotally for the control of eclamptic seizures in the early 1900s, magnesium sulfate remains 1 of the most commonly used medications in obstetric practice today. Over the past 95 years, there have been countless research studies investigating the efficacy of magnesium sulfate for the management of eclampsia, preeclampsia, preterm labor, and most recently for prevention of cerebral palsy. The majority of this evidence undeniably supports the use of magnesium sulfate as the drug of choice for the prevention and treatment of eclampsia when evidence of severe disease is present. On the other hand, studies have not shown magnesium sulfate to be comparably more effective than other tocolytics for treating preterm labor, nor is there agreement on whether the evidence supports its use as a neuroprotective agent for prevention of cerebral palsy. The exact mechanism of action of magnesium sulfate remains largely hypothetical, and parenteral use has the potential to cause significant morbidity in high doses. This article reviews magnesium sulfate's remarkable history in obstetric practice and includes a summary of the evidence related to each of the controversies. An initial review of the physiology of magnesium sulfate is essential to understanding pharmacodynamic actions, dosing guidelines, and safety requirements.

Diagnosis and management of pre-eclampsia: an update

Pre-eclampsia is a significant, multifactorial, multiorgan disease affecting 5%-8% of all pregnancies in the US where it is the third leading cause of maternal mortality. Despite improvements in the diagnosis and management of pre-eclampsia, severe complications can occur in both the mother and the fetus, and there is no effective method of prevention. Early detection and identification of pregnant women most at risk of developing the disease have proven challenging, but recent efforts combining biochemical and biophysical markers are promising. Efforts at prevention of pre-eclampsia with aspirin and calcium have had limited success, but research on modifiable risk factors, such as obesity surgery, are encouraging. Obstetric management of severe pre-eclampsia focuses on medical management of blood pressure and prevention of seizures using magnesium sulfate, but the ultimate cure remains delivery of the fetus and placenta. Timing of delivery depends on several factors, including gestational age, fetal lung maturity, and most importantly, disease severity. Anesthetic management includes regional anesthesia with careful evaluation of the patient's airway, volume status, and coagulation status to reduce morbidity and mortality. The potential complications of general anesthesia, including intracranial hemorrhage, in these patients make regional anesthesia the preferred choice in many cases. Nevertheless, it is important to be aware of the contraindications to neuraxial anesthesia and to prepare always for the possibility of encountering a difficult airway.

Pharmacotherapeutic options for the treatment of preeclampsia

PURPOSE

Pharmacotherapeutic options for the treatment of preeclampsia are reviewed.

SUMMARY

Risk factors for the development of preeclampsia include microvascular diseases, such as diabetes mellitus; vascular and connective tissue disorders; hypertension; antiphospholipid antibody syndrome; and nephropathy. Several pathophysiological factors contribute to the development of the preeclamptic state, including vasospasm onset, coagulation system activation, increased inflammatory response, and ischemia. The specific agents used for the treatment of preeclampsia are dependent on a number of factors including symptom severity, maternal or fetal compromise, the progression to eclampsia, gestational period, and cervical status. The diagnosis of preeclampsia beyond the gestation period of 38 weeks requires delivery. The presence of maternal compromise or eclampsia at gestation greater than 20 weeks also necessitates delivery. In cases of chronic or mild hypertension, oral methyldopa may be administered on an outpatient basis. Intravenous hydralazine is a commonly administered arteriolar vasodilator that is effective for hypertensive emergencies associated with pregnancies. The most common adverse effect of hydralazine administration is unpredictable hypotension. Labetalol decreases heart rate and may be preferred because of a lack of reflex tachycardia, hypotension, or increased intracranial pressure. However, the drug of choice for the prevention and control of maternal seizures in patients with severe preeclampsia or eclampsia during the peripartum period is i.v. magnesium sulfate. Therapeutic serum magnesium levels cause cerebral vasodilation, thereby reversing the ischemia produced by cerebral vasospasm during an eclamptic episode. The results of one study indicated that women receiving magnesium sulfate therapy had a 58% lower risk of eclampsia than placebo.

CONCLUSION

Magnesium sulfate remains the drug of choice for the prevention and treatment of preeclampsia. Alternative antihypertensive agents may provide additional benefit in the management of hypertension for preeclamptic patients.