Eclampsia is a severe, life-threatening manifestation of preeclampsia. While long-term neurologic damage is rare, there is risk of maternal hypoxia and death. Most women will experience signs such as headaches or visual changes prior to a seizure.
Eclampsia
Defined as convulsions during pregnancy and/or postpartum
Tonic-clonic, focal, or multifocal
New onset
Unexplained by other neurologic pathology
Consider other underlying cerebral conditions when
Seizures occur 2 to 3 days postpartum
Patient on magnesium sulfate
Note: Not all women will demonstrate classic features of preeclampsia (hypertension, proteinuria)
Magnesium Sulfate – Seizure Prophylaxis
Magnesium sulfate is the treatment of choice for seizure prophylaxis (ACOG recommended dosing)
Loading dose of 4–6 g of magnesium sulfate administered per infusion pump over 20–30 minutes (i.e., slowly) followed by a maintenance dose of 1-2 g per hour as a continuous intravenous infusion
Continue 24 hours postpartum
Recurrent seizures
Additional dose of 2-4 g can be infused over 5 minutes
Refractory seizures
Sodium amobarbital: 250 mg IV in 3 minutes
Thiopental or phenytoin: 1,250 mg IV at a rate of 50 mg/minute
Patient should be managed in ICU
Consider neuroimaging
IM option
10 g initially as a loading dose (5 g IM in each buttock) followed by 5 g every 4 hours
Use if IV access limited
Mix with 1 mL xylocaine 2% to alleviate pain
Note: Magnesium sulfate should not be considered an antihypertensive agent
Magnesium Sulfate – When to Use
Severe features of preeclampsia
Administer to all women
No severe features of preeclampsia and systolic BP > 140 and < 160 mm Hg or diastolic BP > 90 and < 110 mm Hg
There is no consensus on this matter as prophylaxis will reduce eclampsia but 1 in 100 to 129 women need to be treated and side effects (although not life threatening) will increase
ACOG states that the decision to use magnesium sulfate when severe features are not present should be the decision of the “physician or institution, considering patient values or preferences, and the unique risk-benefit trade-off of each strategy”
Delivery and Postpartum
Vaginal delivery
Continue infusion 24 hours postpartum
Cesarean
Begin infusion (if not yet running) before surgery and continue 24 hours postpartum
Discontinuing prior to operative vaginal birth or cesarean section to avoid uterine atony or anesthetic drug interactions is not recommended
Prevention of Magnesium Sulfate toxicity
Place Foley to monitor renal function (hourly output)
Confirm normal serum creatinine
Serial evaluation of patellar deep tendon reflexes
Monitor respiratory rate
Serum magnesium levels not routinely required
Monitor serum magnesium levels in setting of renal dysfunction and/or absence of patellar reflexes
Maintain serum concentrations 5 to 9 mg/dL (4–7 mEq/L) range
Predictive symptoms of magnesium sulfate toxicity
Loss of deep tendon reflexes >9 mg/dL (greater than 7 mEq/L)
Respiratory depression >12 mg/dL (greater than 10 mEq/L)
Cardiac arrest >30 mg/dL (greater than 25 mEq/L)
Pending toxicity
Notify appropriate health care provider
Discontinue magnesium infusion
Administer supplemental oxygen
Obtain a serum magnesium level
Reverse magnesium
10 mL of 10% calcium gluconate IV (1 g total) and over 3 min (i.e., slowly) to avoid hypotension and/or bradycardia
Calcium effect (competitively inhibits magnesium at neuromuscular junction) can wear off if magnesium level stays high
Furosemide may help increase urinary excretion
Respiratory arrest: Intubation and assisted ventilation as indicated
Other Prophylactic Agents
Magnesium sulfate is superior to diazepam, phenytoin and lytic cocktail (chlorpromazine, promethazine, pethidine) in reducing significantly the risk of seizure recurrence
Cochrane Review 2010: Magnesium sulfate reduced eclampsia compared to phenytoin (relative risk 0.08, 95% CI 0.01 to 0.60)
Morbidity related to pneumonia, mechanical ventilation and admission to an intensive care unit are significantly reduced with the use of magnesium sulfate compared with phenytoin
Magnesium sulfate does not cause maternal or newborn CNS depression
Diazepam or lorazepam does stop or shorten seizures, but risk of maternal apnea and/or cardiac arrest
ACOG Guidance: Emergency Treatment for Severe Hypertension in Pregnancy
Summary:
Severe hypertension can be a life-threatening event during pregnancy and requires special vigilance in the postpartum period, particularly following hospital discharge. The goal of treatment is to control hypertension and prevent seizures. Uncontrolled hypertension can lead to heart failure, myocardial ischemia, renal injury and stroke.
When to Treat:
Urgently treat acute onset severe hypertension in pregnancy or postpartum period
SBP ≥160 and and/or DBP ≥110 mm Hg persisting for 15 minutes
systolic BP a predictor of maternal morbidity/mortality
Note: ACOG states that “any of these agents can be used to treat acute severe hypertension in pregnancy” | An approach detailed in ACOG guidance uses “an initial regimen of labetalol at 200 mg orally every 12 hours and increase the dose up to 800 mg orally every 8–12 hours as needed (maximum total 2,400 mg/d). If the maximum dose is inadequate to achieve the desired blood pressure goal, or the dosage is limited by adverse effect, then short-acting oral nifedipine can be added gradually”
Seizure Prophylaxis: Magnesium Sulfate
Remains drug of choice for seizure prophylaxis
Magnesium sulfate should not be used to reduce blood pressure
See more on magnesium sulfate in ‘Related ObG Topics’
When to Use
Severe features of preeclampsia
Administer to all women
No severe features of preeclampsia and systolic BP > 140 and < 160 mm Hg or diastolic BP > 90 and < 110 mm Hg
There is no consensus on this matter as prophylaxis will reduce eclampsia but 1 in 100 to 129 women need to be treated and side effects (although not life threatening) will increase
ACOG states that the decision to use magnesium sulfate when severe features are not present should be the decision of the “physician or institution, considering patient values or preferences, and the unique risk-benefit trade-off of each strategy”
Delivery and Postpartum
Vaginal delivery
Continue infusion 24 hours postpartum
Cesarean
Begin infusion (if not yet running) before surgery and continue 24 hours postpartum
Discontinuing prior to operative vaginal birth or cesarean section to avoid uterine atony or anesthetic drug interactions is not recommended
Administration
Loading dose of 4 to 6 g administered per infusion pump over 20 to 30 minutes (i.e., slowly) followed by a maintenance dose of 1 to 2 g per hour as a continuous intravenous infusion
IM option if IV access limited
10 g initially as a loading dose (5 g IM in each buttock) followed by 5 g every 4 hours
Aspirin Treatment for Women at Risk for Preeclampsia – ACOG, SMFM and USPSTF Recommendations
FINDINGS:
ACOG/SMFM have released guidance aligned with USPSTF regarding the use of low-dose aspirin during pregnancy to prevent preeclampsia. When indicated, low-dose aspirin should be started between 12 to 28 weeks and continued until delivery. Optimally, aspirin usage should begin <16 weeks.
Recommended (high risk)
Offer low-dose aspirin (81 mg/day) to women with ≥1 high risk factors
History of preeclampsia, especially if accompanied by an adverse outcome
Multifetal gestation
Chronic hypertension
Diabetes (Type 1 or Type 2)
Renal disease
Autoimmune disease (for example, systematic lupus erythematosus, antiphospholipid syndrome)
Moderate Risk Factors
Offer low-dose aspirin (81 mg/day) to women with ≥2 moderate risk factors
Nulliparity
Obesity (BMI >30)
Personal history
Low birthweight or SGA
Previous adverse pregnancy outcome
>10-year pregnancy interval
Family history of preeclampsia
Sister or mother
Social and demographic characteristics
Black race (as a proxy for underlying racism)
Lower income
Maternal age ≥35 years
IVF
Note: USPSTF does allow for consideration of aspirin prophylaxis if ≥1 moderate risk factor is present and states “Clinicians should use clinical judgment in assessing the risk for preeclampsia and discuss the benefits and harms of low-dose aspirin use with their patients”
Universal Implementation
Evidence supports a risk-based approach
ACOG/SMFM acknowledges that in some settings, a majority of patients will fall in to either high or moderate risk categories, and therefore
In these instances, universal implementation (eg, offering low-dose aspirin to all patients within such practices or institutions) may be medically reasonable
The USPSTF recommends the use of low-dose aspirin (81 mg/d) as preventive medication for preeclampsia after 12 weeks of gestation in persons who are at high risk for preeclampsia as per categories above (B recommendation – offer or provide this service)
Benefits
The most recent systematic evidence review (see ‘Learn More – Primary Sources) provided more precise estimate of the association between aspirin and the prevention of perinatal mortality (4% to 44% reduction in fetal and neonatal deaths)
Otherwise, benefits of low-dose aspirin for women at risk for preeclampsia were similar to previous reviews with lower risks for the following (moderate certainty)
Preeclampsia: Pooled relative risk (RR) 0.85 (95% CI, 0.75-0.95)
Perinatal mortality: Pooled RR 0.79 (95% CI, 0.66-0.96)
Preterm birth: Pooled RR 0.80 (95% CI, 0.67-0.95)
Intrauterine growth restriction: Pooled RR 0.82 (95% CI, 0.68-0.99)
Harms
No significant association was found for
PPH or other bleeding-related harms
Rare perinatal or longer-term harms
Long-term child developmental outcomes in offspring from in utero exposure to low-dose aspirin
Follow-up data from the Collaborative Low-dose Aspirin Study in Pregnancy (CLASP), found no differences in physical or developmental outcomes at 12 to 18 months
KEY POINTS:
Risk factors used for ACOG/SMFM recommendations only include factors obtained from the medical record
Uterine artery Doppler ultrasonography and biochemical markers are not included
ACOG/SMFM acknowledge that other studies, in particular the ASPRE trial (see ‘Related ObG Topics’ below), have incorporated ultrasound and maternal serum markers as well as doses >81 mg, but state
Further, the screening algorithm used includes first-trimester serum markers, including placental growth factor and pregnancy-associated plasma protein-A, as well as uterine artery dopplers, which limits the generalizability to a U.S. population. Therefore, a higher dose or doubling of the available 81-mg dose cannot be recommended at this time.
Screening for Preeclampsia
Various studies have incorporated not only clinical risk factors but also biochemical markers and ultrasound to determine which women are at risk for early onset preeclampsia and may benefit from aspirin prevention (see ‘Related ObG Topics’)
ACOG/SMFM considers the supporting data for the use of such combined risk assessment algorithms to be limited and without more prospective clinical utility trials, states that
…biomarkers and ultrasonography cannot accurately predict preeclampsia and should remain investigational.
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This educational activity may contain discussion of published and/or investigational uses of agents that are not indicated by the FDA. The planners of this activity do not recommend the use of any agent outside of the labeled indications.
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presented in this activity is not meant to serve as a guideline for patient management. Any procedures, medications, or other courses of diagnosis or treatment discussed or suggested in this activity should not be used by clinicians without evaluation of their patient’s conditions and possible contraindications and/or dangers in use, review of any applicable manufacturer’s product information, and comparison with recommendations of other authorities.
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