Gestational Hypertension: Management

1. Definition and Diagnosis

• SBP ≥ 140 mmHg and/or DBP ≥ 90 mmHg on two occasions at least 4 hours apart
• Severe-range: SBP ≥ 160 or DBP ≥ 110 mmHg (can be confirmed within minutes)
• Must resolve within 3 months postpartum; if it persists, reclassify as chronic hypertension

2. Monitoring Protocol

• BP assessment at least weekly
• Weekly symptoms review (headache, visual changes, epigastric pain - signs of evolving severe features)
• Weekly lab work: CBC, liver enzymes, serum creatinine
• Weekly fetal assessment: non-stress test (NST) or biophysical profile (BPP)
• Amniotic fluid index assessment at least weekly
• Fetal growth ultrasonography every 3 weeks

3. BP Treatment Thresholds and Targets

4. Antihypertensive Pharmacotherapy

First-Line Oral Agents

IV Agents for Acute Severe Hypertension

• Labetalol IV: first-line for acute severe episodes
• Hydralazine IV: alternative
• Nifedipine (oral): can also be used for acute BP control
• Labetalol is specifically recommended for hypertensive emergencies in pregnancy - Lippincott Pharmacology

Absolutely Contraindicated in Pregnancy

• ACE inhibitors and ARBs: associated with fetal renal dysplasia, oligohydramnios, and pulmonary hypoplasia (second/third trimester exposure)
• Diuretics: not first-line; should not be used in preeclampsia (may worsen uteroplacental flow)

5. Delivery Timing

GH Without Severe Features

GH/Preeclampsia With Severe Features

• ≥ 34 weeks: Deliver after stabilization with antihypertensives and magnesium
• < 34 weeks: Short-term expectant management ONLY in tertiary-level facilities with careful monitoring; deliver if maternal or fetal condition deteriorates
• Any gestational age: Immediate delivery for eclampsia, pulmonary edema, uncontrollable severe hypertension, non-reassuring fetal status

6. Magnesium Sulfate

• Recommended for all women with preeclampsia WITH severe features - for seizure prophylaxis (eclampsia prevention)
• Not routinely recommended for GH or preeclampsia WITHOUT severe features (ACOG guidance; the benefit is unclear, and no eclamptic seizures occurred in placebo arms of RCTs in this group)
• Dose: 4-6 g IV loading dose, then 1-2 g/hr maintenance
• Monitor for toxicity: loss of patellar reflexes (first sign), respiratory depression, cardiac arrest

7. Postpartum Management

• Hypertension often persists or worsens in the first 48-72 hours postpartum
• Continue antihypertensives if BP ≥ 150/100 mmHg postpartum
• Home BP monitoring is recommended postpartum
• If BP does not normalize within 6 weeks, reclassify as chronic hypertension
• These women have elevated long-term cardiovascular risk - requires longitudinal follow-up and risk factor modification - Braunwald's Heart Disease, p. 1072

8. Preeclampsia Prevention (Aspirin)

• Low-dose aspirin (81 mg/day) initiated between 12-16 weeks (no later than 20 weeks), continued until ≥ 36 weeks
• Indicated with any high-risk factor: chronic HTN, prior preeclampsia, multifetal gestation, diabetes, renal disease, autoimmune disease
• Also indicated with >1 moderate risk factor: nulliparity, BMI > 30, family history, age ≥ 35 - Braunwald's Heart Disease, p. 1072

9. Fetal Considerations

• Offspring of GH mothers are at increased risk for preterm delivery and intrauterine growth restriction (IUGR)
• Fetal growth surveillance (ultrasound every 3 weeks) and weekly antenatal testing are standard throughout expectant management

Summary Algorithm

GH Diagnosed (≥20 wks, BP ≥140/90, no proteinuria)
  │
  ├─ Assess severity: labs, symptoms, fetal status
  │
  ├─ Treat if BP ≥160/110 (acute IV/oral agents)
  │
  ├─ ≥37 weeks → Deliver
  │
  └─ <37 weeks → Expectant management
        Weekly BP, labs, NST, AFI
        Growth scan q3 weeks
        Steroids if <34 weeks
        Deliver if severe features develop