Treatment Guidelines: Preeclampsia and Gestational Hypertension

Classification of Hypertensive Disorders of Pregnancy (HDP)

• Harrison's Principles of Internal Medicine 22E (2025)
• NKF Primer on Kidney Diseases, 8e

Diagnostic Criteria

Preeclampsia

• BP ≥140/90 mmHg on two measurements 4 h apart, after 20 weeks
• Plus proteinuria: 24-h urine protein >300 mg OR protein:creatinine ratio ≥0.3
• Preeclampsia can be diagnosed without proteinuria if signs of end-organ damage are present

Severe Features (any one qualifies)

• BP ≥160/110 mmHg
• Headache unresponsive to medications, visual changes, or severe epigastric pain
• Pulmonary edema
• Thrombocytopenia (platelets <100 × 10⁹/L)
• Renal insufficiency (creatinine >1.1 mg/dL)
• Liver impairment (transaminases >2x normal)

Eclampsia

• Generalized tonic-clonic seizures in a patient with preeclampsia

HELLP Syndrome

• Hemolysis, Elevated Liver enzymes, Low Platelets - a severe preeclampsia subtype
• Harrison's, p. 3942

Gestational Hypertension - Management

• BP ≥140/90 after 20 weeks without proteinuria or end-organ damage
• 15-25% of patients will progress to overt preeclampsia - close monitoring is required
• Associated with increased risk of preterm delivery and IUGR even without preeclampsia
• Women are at increased lifetime risk for hypertension and cardiovascular disease

• Close monitoring for development of preeclampsia features
• Blood pressure control when severe (≥160/105 mmHg) - drug therapy is clearly indicated
• The CHIPS trial showed treating to a diastolic target of 85 mmHg is safe for the fetus and reduces progression to severe HTN
• Delivery at term
• NKF Primer on Kidney Diseases, 8e, p. 490

Preeclampsia Without Severe Features

• Delivery at 37 weeks is recommended
• Expectant management is standard until 37 weeks if no severe features develop
• Management includes:
  • Close monitoring for development of severe features or lab abnormalities
  • Frequent fetal surveillance
  • Limited physical activity / bed rest (the only demonstrated means of reducing BP to prolong pregnancy)
  • BP documentation, reflexes, weight, blood testing for end-organ function
  • Accurate gestational age assessment by ultrasound
• Harrison's 22E; Rosen's Emergency Medicine, 9e

Preeclampsia With Severe Features

• Patient is <34 weeks and eligible for expectant management at a tertiary hospital

• Unrelenting symptoms
• Worsening laboratory abnormalities
• Severe-range BPs refractory to medical management
• Severe fetal growth restriction or placental abruption

Step-by-Step Management (Parkland Protocol)

1. Seizure prophylaxis/control: Magnesium sulfate 4-6 g IV over 15-20 minutes, then 2 g/hr IV continuous infusion
2. Antihypertensive treatment (initiate after seizure control if diastolic BP >105 mmHg):
   • Hydralazine 5-10 mg IV push, repeat q2-4h
   • Labetalol 20 mg IV bolus, repeat q10 min PRN up to 300 mg total
3. Lab workup: CBC + platelets, LFTs, BUN/creatinine, coagulation profile, baseline Mg level
4. Fluid management: Maintain urine output >25 mL/hr; limit IV fluids; avoid diuretics and hyperosmotic agents
5. Fetal monitoring: Continuous
6. Initiate steps toward delivery

• Rosen's Emergency Medicine, 9e (Box 173.4)

Eclampsia Management

• Magnesium sulfate is the anticonvulsant of choice - it terminates seizures and prevents recurrence while maintaining uteroplacental blood flow (unlike other anticonvulsants)
• Loading dose: 4-6 g IV over 15-20 minutes, then 2 g/hr IV maintenance
• Monitor for hypermagnesemia:
  • Loss of reflexes occurs at ~10 mg/dL
  • Respiratory depression occurs at ~12 mg/dL
  • Antidote: Calcium gluconate 1 g IV slowly
• If seizures are refractory to MgSO4, consider CT head to rule out intracranial hemorrhage or cerebral venous thrombosis
• Maternal mortality from eclampsia is <1% with modern management; perinatal mortality remains 4-8%

Antihypertensive Drug Selection in Pregnancy

Oral Agents (Chronic/Gestational HTN)

IV Agents (Acute Severe Hypertension)

• Labetalol 20 mg IV bolus q10 min, up to 300 mg total
• Hydralazine 5-10 mg IV q2-4h
• Oral nifedipine may be considered once BP is controlled

Contraindicated in Pregnancy

• ACE inhibitors - fetal renal dysplasia, oligohydramnios, pulmonary hypoplasia (2nd trimester onward)
• ARBs - same mechanism, associated with stillbirth and congenital anomalies
• Diuretics - not first-line; contraindicated in preeclampsia (volume contraction worsens placental perfusion)
• NKF Primer on Kidney Diseases, 8e, Table 47.1; Harrison's 22E

Preeclampsia Prevention

• Low-dose aspirin initiated between 12-14 weeks reduces risk in women at high risk of preeclampsia
• Risk factors warranting aspirin prophylaxis: nulliparity with risk factors, prior preeclampsia, multifetal gestation, chronic HTN, diabetes, CKD, obesity, antiphospholipid antibody syndrome

Chronic Hypertension in Pregnancy

• At increased risk for superimposed preeclampsia (25%), IUGR (17%), perinatal mortality (4%)
• Target BP: <140/90 mmHg (reduces risk of developing preeclampsia and preterm birth)
• Preferred agents: labetalol, extended-release nifedipine
• Discontinue ACE inhibitors/ARBs before conception or as early as possible in pregnancy
• Preconception assessment for end-organ damage (especially proteinuria) is helpful to later distinguish effects of chronic HTN from superimposed preeclampsia

Long-Term Implications

• Women who have had preeclampsia or gestational hypertension are at increased lifetime risk for hypertension and cardiovascular disease
• Cardiovascular risk reduction strategies should be initiated at postpartum health encounters
• Harrison's 22E; NKF Primer on Kidney Diseases, 8e