What is the management of active seizure in a pregnant patient?

From the Guidelines

Active seizure management in pregnant patients should prioritize magnesium sulfate as the first-line treatment, especially if eclampsia is suspected, with a dose of 4-6 g IV over 15-20 minutes followed by 1-2 g/hour infusion. This approach is based on the most recent and highest quality evidence available, which emphasizes the importance of prompt and effective seizure control to prevent maternal and fetal morbidity and mortality 1. The use of magnesium sulfate is recommended for the prevention of eclampsia and treatment of seizures, and it is considered a safe and effective treatment option for pregnant women.

Key Considerations

• Magnesium sulfate should be administered intravenously, with a loading dose of 4-6 g over 15-20 minutes, followed by a maintenance infusion of 1-2 g/hour 1.
• It is essential to monitor the patient's vital signs, including blood pressure, heart rate, and respiratory rate, during magnesium sulfate administration.
• Fetal heart rate monitoring should also be performed if the gestational age is viable.
• Benzodiazepines, such as lorazepam or midazolam, may be considered as alternative or adjunctive treatments for seizure control, but magnesium sulfate remains the first-line treatment for eclampsia 1.

Underlying Causes

• Eclampsia is a significant cause of seizures in pregnant women, and magnesium sulfate is the treatment of choice for this condition.
• Other underlying causes of seizures, such as preeclampsia or hypertensive disorders, should be addressed concurrently with seizure management.
• The patient's blood pressure should be monitored and managed according to guidelines, with a target diastolic blood pressure of 85 mm Hg in the office (and systolic blood pressure of 110–140 mm Hg) to reduce the likelihood of developing severe maternal hypertension and other complications 1.

Monitoring and Support

• The patient should be positioned in the left lateral decubitus position to prevent aortocaval compression and promote maternal and fetal well-being.
• Supplemental oxygen should be administered to maintain maternal oxygenation and prevent hypoxic injury.
• Close monitoring of the patient's condition, including fetal heart rate and maternal vital signs, is essential to ensure prompt detection and management of any complications that may arise.

From the FDA Drug Label

In humans, prenatal exposure to phenytoin may increase the risks for congenital malformations and other adverse developmental outcomes. An increase in seizure frequency may occur during pregnancy because of altered phenytoin pharmacokinetics. Periodic measurement of serum phenytoin concentrations may be valuable in the management of pregnant women as a guide to appropriate adjustment of dosage

The management of active seizure in a pregnant patient taking phenytoin involves:

• Monitoring serum phenytoin concentrations to adjust the dosage as needed
• Being aware of the potential for increased seizure frequency during pregnancy due to altered phenytoin pharmacokinetics
• Considering the risks of congenital malformations and other adverse developmental outcomes associated with prenatal exposure to phenytoin 2
• Counseling patients about the importance of notifying their physician if they become pregnant or intend to become pregnant during therapy, and encouraging them to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry 2

From the Research

Active Seizure in Pregnant Patient Management

• Seizures in pregnancy pose risks for both the mother and the fetus and must be managed aggressively 3
• The evaluation of a pregnant woman with new-onset seizures is the same as for the nonpregnant patient, including head computed tomography with appropriate abdominal shielding 3
• Status epilepticus management is based on IV benzodiazepines, phenytoin, or phenobarbital, and good fetal outcome is dependent on rapid seizure control 3

Diagnosis and Management

• Most seizures during pregnancy occur in women who already have epilepsy, and during pregnancy, most women will continue their previous level of seizure control, although 15-30% may experience an increase in seizures 4
• Pregnancy-induced changes in antiepileptic drug pharmacokinetics are a major factor affecting changes in seizure control during pregnancy, although compliance is also a significant factor 4
• Structural and metabolic changes may precipitate new-onset seizures during pregnancy, including intracranial hemorrhage, cerebral venous sinus thrombosis, and ischemic stroke, as well as hyperemesis gravidarum, acute hepatitis, and eclampsia 4

Role of Magnesium Sulfate

• Magnesium sulfate is a significantly better drug than either diazepam or phenytoin for preventing recurrent seizures in eclamptic patients 5
• Magnesium sulfate has diverse cardiovascular and neurological effects and also alters calcium metabolism, and although it crosses the placenta and may affect the fetus, these effects are clinically small and fetal morbidity has been shown to be reduced in randomized studies 5
• The duration of postpartum magnesium sulfate for seizure prophylaxis in women with preeclampsia does not affect the incidence of seizures postpartum, but women who received <24 h of postpartum magnesium sulfate had a significantly faster time to ambulation postpartum and shorter durations of indwelling urinary catheter placement 6

Management of Epilepsy During Pregnancy

• Managing epilepsy during pregnancy is to balance the maternal and fetal risks associated with uncontrolled seizures against the potential teratogenic effects of antiepileptic drugs (AEDs) 7
• Uncontrolled tonic-clonic seizures are potentially hazardous to the mother and, although strict evidence is lacking, are generally also assumed to be more harmful to the fetus than are AEDs 7
• Infants who have been exposed to AEDs in utero run an increased risk of congenital malformations, approximately twice the rate reported in the general population, and valproic acid appears to be associated with a higher risk of birth defects compared with some other major AEDs 7