Chapter 14: Preeclampsia and Eclampsia

PATHOPHYSIOLOGY AND CLINICAL PRESENTATION OF PREECLAMPSIA

• Multisystem disease attributable to endothelial dysfunction.

• Preeclampsia is clinically defined by new onset (after 20 weeks of gestation) of hypertension (systolic blood pressure [SBP] ≥140 mm Hg or diastolic blood pressure [DBP] ≥90 mm Hg) and proteinuria. Preeclampsia can also be diagnosed in the absence of proteinuria, if one or more systemic manifestations are present (see Table 14-1).¹

• Preeclampsia is said to have severe features if blood pressure is high, i.e., SBP ≥160 mm Hg or DBP ≥110 mm Hg, or with the presence of one or more systemic manifestations (see below).¹

• Early onset (<34 weeks gestational age) preeclampsia typically carries greater risk of maternal/fetal complications (see Table 14-2).

• Occurrence of seizures not attributable to any other cause = eclampsia (seizure may be a presenting sign).

CLINICAL MANAGEMENT

Obstetric Decision-Making Examples¹

Preeclampsia without severe features: continued monitoring and expectant management until 37 weeks of gestational age, then induction of labor (or cesarean delivery if obstetric indication is present).

Preeclampsia with severe features:

• ≥34 weeks of gestational age, delivery is recommended after maternal stabilization.

• <34 weeks of gestational age with stable maternal and fetal condition, expectant management may be considered.

• <34 weeks of gestational age with any clinical instability, delivery soon after maternal stabilization.

Intrapartum Management Cornerstones

1. Blood pressure (BP) monitoring and treatment:

   • At least once per hour predelivery

   • Automated BP cuff may underestimate actual BP. Check with manual cuff. Place arterial line for monitoring if divergent.

   • Target SBP <160 mm Hg, DBP <110 mm Hg. Be aware that excessive lowering BP can cause a rapid decrease in uteroplacental perfusion.

   • First-line therapy: labetalol; second-line: hydralazine, nifedipine.

2. Seizure prophylaxis²:

   • Magnesium sulfate 4 to 6 g intravenous bolus followed by 1 to 2 g/h infusion (renally cleared; reduce dose if renal insufficiency).

   • Target range: 5 to 9 mg/dL.

   • Signs of toxicity: loss of deep tendon reflexes (9.6-12 mg/dL), hypotension, respiratory depression (12-18 mg/dL), hypoxia, EKG changes, and cardiac arrest (24-30 mg/dL).

   • Treatment of magnesium toxicity: CaCl₂ intravenously.

3. Mild fluid restriction (<1 mL/kg/h maintenance during induction of labor and ...