Below is a streamlined, up-to-date summary of “Hypertension in Pregnancy” incorporating key points from established guidelines (primarily ACOG) and more recent considerations. It is intended for medical professionals to quickly reference.
1. Definition and Classification
Definition of Hypertension in Pregnancy
Blood pressure (BP) ≥ 140/90 mmHg on two occasions at least 4 hours apart.
Considered “severe-range” if BP ≥ 160/110 mmHg, confirmed within about 15 minutes.
Four Main Categories (ACOG):
Preeclampsia–Eclampsia
New-onset hypertension after 20 weeks’ gestation with either proteinuria or other systemic findings (liver dysfunction, thrombocytopenia, renal insufficiency, neurological or hematological complications).
Eclampsia = new-onset seizures not attributable to other causes.
Chronic Hypertension
Hypertension present before pregnancy or diagnosed before 20 weeks’ gestation, or persisting >12 weeks postpartum.
Chronic Hypertension with Superimposed Preeclampsia
Worsening BP or newly developing proteinuria/other systemic features in a patient with chronic hypertension.
Gestational Hypertension
New-onset hypertension after 20 weeks’ gestation without proteinuria or severe features.
2. Key Diagnostic Criteria
New-onset Hypertension
Systolic BP ≥ 140 mmHg or Diastolic BP ≥ 90 mmHg.
Severe if Systolic ≥ 160 mmHg or Diastolic ≥ 110 mmHg.
Proteinuria (if available)
24-hour urine protein ≥ 300 mg/24 hr, or
Protein/Creatinine ratio ≥ 0.3 mg/dL, or
Urine dipstick ≥ 2+ (only if quantitative methods are unavailable).
Severe Features
Severe-range BP (≥ 160/110 mmHg).
Thrombocytopenia (Platelet <100,000/µL).
Renal insufficiency (Creatinine >1.1 mg/dL or doubled from baseline).
Elevated liver enzymes (AST/ALT ≥2× upper limit).
Persistent epigastric or right upper-quadrant pain.
Neurological signs (new-onset headache unresponsive to meds or visual disturbances).
Pulmonary edema.
Note: Preeclampsia with severe features can be diagnosed even without proteinuria if other severe criteria are present.
3. Pathophysiology (Brief Overview)
Abnormal placentation (reduced trophoblastic invasion of spiral arteries) leads to placental ischemia.
Placental ischemia leads to release of antiangiogenic factors (e.g. sFlt-1) and inflammatory cytokines, causing:
Widespread endothelial dysfunction.
Vasoconstriction, increased capillary permeability, and coagulation abnormalities.
Recent developments include growing use of sFlt-1/PlGF ratio testing in some centers to aid in ruling in/out preeclampsia—especially for patients with uncertain clinical findings (FDA clearance in 2023).
4. Prevention
Low-dose Aspirin (81 mg daily)
Recommended for patients at high risk of preeclampsia (e.g., prior preeclampsia, chronic hypertension, CKD, multifetal gestation) or with multiple moderate-risk factors.
Start between 12–16 weeks gestation, continue until delivery.
Calcium Supplementation
May be beneficial in populations with low dietary calcium intake.
Lifestyle
Bed rest, sodium restriction, vitamins (C/E/D), folic acid, fish oil, or garlic have not demonstrated clear prevention of preeclampsia.
5. Management by Disease Category
A. Chronic Hypertension
Goal BP: Typically 120–160/80–110 mmHg.
Initiate or optimize oral antihypertensives if BP ≥160/110 mmHg (some clinicians may start at lower thresholds around 150/100).
Preferred: Labetalol, nifedipine, or methyldopa.
Avoid: ACE inhibitors, ARBs, mineralocorticoid receptor antagonists.
Fetal Surveillance:
Consider Non-Stress Tests (NST) weekly or biweekly, and routine growth ultrasounds (especially third trimester).
Timing of Delivery:
Generally, no earlier than 37–38 weeks if stable without superimposed preeclampsia.
B. Gestational Hypertension (Without Severe Features)
Admit initially to exclude severe features.
No routine oral antihypertensives unless BP hits severe ranges (≥160/110 mmHg).
Close outpatient follow-up with weekly or twice-weekly BP checks, symptom checks, and fetal surveillance.
Delivery at 37 weeks if stable.
C. Preeclampsia (Without Severe Features)
Manage similarly to gestational hypertension:
Hospital observation to rule out severe features.
No routine antihypertensives unless severe-range.
Delivery at 37 weeks if stable.
D. Preeclampsia/Superimposed Preeclampsia with Severe Features
Definitive Treatment = Delivery
If ≥34 weeks: Proceed to delivery.
If <34 weeks: Consider expectant management (hospitalization, steroids for fetal lung maturity, close maternal-fetal monitoring) if stable, but deliver promptly if deterioration occurs.
Acute BP Control (Short-acting antihypertensives):
IV labetalol or hydralazine, or oral immediate-release nifedipine to keep BP <160/110 mmHg and prevent stroke.
Seizure Prophylaxis:
IV Magnesium Sulfate for severe preeclampsia/eclampsia.
Monitor for magnesium toxicity (respirations, deep tendon reflexes, urine output).
Intrapartum & Postpartum:
Continue magnesium sulfate through labor and 24 hours postpartum.
Vigilance for postpartum stroke, pulmonary edema, or HELLP syndrome progression.
E. HELLP Syndrome (Hemolysis, Elevated Liver Enzymes, Low Platelets)
Managed as severe preeclampsia with heightened vigilance.
Delivery indicated if ≥34 weeks or maternal/fetal status worsens regardless of gestational age.
F. Eclampsia
Seizure management: Magnesium sulfate (bolus + maintenance).
Supportive measures (airway protection, oxygen, hemodynamic stabilization).
Deliver once mother is stabilized; eclampsia is not an absolute indication for cesarean unless obstetric factors dictate.
6. Postpartum Management
Continue Monitoring: Hypertension, fluid balance, signs of organ dysfunction can worsen in the first 24–72 hours postpartum.
Severe preeclampsia: Continue magnesium sulfate for 24 hours postpartum.
Avoid Methylergonovine in hypertensive patients (can escalate BP).
Follow-up at 1–2 weeks postpartum for BP recheck. Hypertension persisting >12 weeks postpartum = Chronic Hypertension diagnosis.
7. Long-Term Health Implications
History of preeclampsia or gestational hypertension increases lifetime risk of cardiovascular disease (CVD).
Encourage postpartum patients to adopt lifestyle modifications (healthy diet, exercise, weight management) and follow appropriate primary care or cardiology follow-up.
8. Recent/Upcoming Updates
sFlt-1/PlGF ratio testing gained more widespread adoption (FDA-cleared in 2023) to help rule in/out preeclampsia in uncertain cases.
Aspirin prophylaxis remains a cornerstone for those at high risk, with evidence supporting 81–150 mg daily in some newer studies.
Potential novel therapies targeting angiogenic/antiangiogenic pathways under investigation but not yet standard of care.
Bottom Line
Hypertensive disorders of pregnancy remain a leading cause of maternal–fetal morbidity and mortality. Early identification, close surveillance, correct classification, timely intervention (BP control, seizure prophylaxis, and proper timing of delivery), and postpartum follow-up are crucial for optimizing outcomes. Newer biomarker tests (e.g., sFlt-1/PlGF ratio) and the continued use of low-dose aspirin prophylaxis in high-risk women reflect ongoing advancements in the field.
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