Evaluation of pregnant patients ≥20 weeks gestation with new-onset hypertension.
Assessment of postpartum patients (up to 6 weeks) presenting with hypertension or headache.
Differentiating gestational hypertension from preeclampsia.
Identifying preeclampsia with severe features requiring immediate hospitalization.
Blood Pressure Thresholds
Diagnosis requires Systolic BP ≥140 mmHg or Diastolic BP ≥90 mmHg on two occasions at least 4 hours apart. Severe range BP (≥160/110) can be confirmed within minutes to facilitate rapid antihypertensive therapy.
Section 2
Formula & Logic
Diagnostic Criteria
New-onset HTN (≥140/90) AFTER 20 weeks gestation PLUS:
Proteinuria (≥300 mg/24h, P:C ratio ≥0.3, or 2+ dipstick)
OR (in the absence of proteinuria) new-onset systemic dysfunction:
Platelets < 100,000/μL
Serum creatinine > 1.1 mg/dL (or doubling in absence of renal disease)
Liver transaminases 2x upper limit of normal
Pulmonary edema
New-onset cerebral or visual disturbances
Defining "Severe Features"
Blood Pressure
SBP ≥160 or DBP ≥110
Thrombocytopenia
< 100,000/μL
Liver Function
Severe RUQ pain or 2x LFTs
Renal Insufficiency
Cr > 1.1 mg/dL
Pulmonary
Pulmonary Edema
Neurological
New headache, scotomata, clonus
Section 3
Pearls/Pitfalls
Critical Pearls
Proteinuria is NO LONGER required for diagnosis if other systemic features are present.
"Mild" preeclampsia is an obsolete term; the condition is now categorized as "Preeclampsia without Severe Features" or "Preeclampsia with Severe Features."
Postpartum preeclampsia: Up to 30% of eclamptic seizures occur postpartum, often in patients who were normotensive at discharge.
Epigastric pain is often misdiagnosed as GERD; in a hypertensive gravid patient, it is a marker of hepatic capsular stretch and a severe feature.
Risk Factors for Prophylaxis
High-risk patients (Prior preeclampsia, multifetal gestation, CKD, autoimmune disease, T1DM/T2DM, chronic HTN) should be started on low-dose Aspirin (81–162 mg/day) between 12 and 28 weeks gestation.
Section 4
Next Steps
Management: Without Severe Features
01
Serial labs (CBC, LFTs, Cr) and BP monitoring 1–2x weekly.
02
Fetal surveillance (NST/BPP) and serial growth scans.
03
Delivery indicated at 37 0/7 weeks gestation.
Management: With Severe Features
01
Hospitalization for the duration of pregnancy.
02
Magnesium Sulfate for seizure prophylaxis.
03
Antihypertensives (Labetalol, Hydralazine, or Nifedipine) for SBP ≥160 or DBP ≥110.
04
Delivery indicated at 34 0/7 weeks (or earlier if maternal/fetal condition destabilizes).
05
Administer corticosteroids for fetal lung maturity if <34 weeks.
Differential Diagnosis
HELLP Syndrome Criteria
Chronic vs Gestational Hypertension
AFLP (Acute Fatty Liver of Pregnancy)
Section 5
Evidence Appraisal
Current Gold Standard
Gestational Hypertension and Preeclampsia: ACOG Practice Bulletin, Number 222.
ACOG (American College of Obstetricians and Gynecologists) • Obstet Gynecol.. 2020;Current definitive guideline for diagnosis and management in the United States.
Seizure Prophylaxis Evidence
Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial.
Altman D et al. • Lancet.. 2002;Landmark trial (n=10,141) establishing magnesium sulfate as the superior agent for preventing eclampsia (58% risk reduction).
Section 6
Literature
Evolution of the Diagnosis
Historically known as "toxemia," preeclampsia was long thought to be caused by a circulating toxin. We now recognize it as a complex multisystem syndrome driven by placental malperfusion and systemic endothelial dysfunction.
The Move Away from Proteinuria
In 2013, the ACOG Task Force on Hypertension in Pregnancy fundamentally changed the diagnostic landscape by removing the absolute requirement for proteinuria, recognizing that women can progress to eclamptic seizures or HELLP syndrome without significant renal protein excretion.
