Hypertension of Pregnancy

Overview

Hypertension of pregnancy represents a group of conditions characterized by high blood pressure that develops during pregnancy or is first recognized during pregnancy. These disorders exist on a continuum of severity and include gestational hypertension, preeclampsia, eclampsia, chronic hypertension with superimposed preeclampsia, and HELLP syndrome. Understanding these conditions is vital as they can significantly impact maternal and fetal health, potentially leading to serious complications if not properly managed.

The classification of hypertensive disorders in pregnancy has evolved to reflect our growing understanding of their pathophysiology. Gestational hypertension, the mildest form, involves elevated blood pressure without other signs of organ dysfunction. Preeclampsia, affecting 3-5% of pregnancies, involves hypertension plus evidence of organ involvement, typically manifested as proteinuria or other systemic findings. Eclampsia, the most severe form, includes seizures in addition to preeclampsia features. These conditions can progress rapidly, making vigilant monitoring essential throughout pregnancy and the postpartum period.

The impact of hypertensive disorders extends beyond the immediate pregnancy. Women who develop these conditions face increased risks of cardiovascular disease, kidney disease, and metabolic disorders later in life. For the developing fetus, maternal hypertension can lead to growth restriction, preterm birth, and long-term developmental consequences. This dual impact underscores the importance of not only managing the acute condition but also ensuring appropriate long-term follow-up for affected women. Modern obstetric care has significantly improved outcomes, but these conditions remain a major cause of maternal and perinatal morbidity and mortality globally.

Symptoms

The symptoms of hypertension in pregnancy can range from subtle to severe, and some women may have no symptoms despite having dangerously high blood pressure. Early recognition of warning signs is crucial for preventing progression to more severe complications. Healthcare providers closely monitor for these symptoms during prenatal visits.

Early and Common Symptoms

• Headache - Often severe, persistent, and not relieved by usual remedies
• Blood pressure readings ≥140/90 mmHg on two occasions
• Swelling (edema) in hands, face, or around eyes
• Sudden weight gain (more than 2 pounds per week)
• Visual disturbances - blurry vision, seeing spots or flashing lights

Gastrointestinal Symptoms

• Heartburn - More severe than typical pregnancy heartburn
• Nausea and vomiting in the second half of pregnancy
• Upper abdominal pain, especially under the ribs on the right side
• Decreased appetite

Pregnancy-Specific Symptoms

• Pain during pregnancy - Particularly epigastric or right upper quadrant
• Problems during pregnancy - Including decreased fetal movement
• Spotting or bleeding during pregnancy
• Uterine contractions - May indicate placental problems

Severe Preeclampsia Symptoms

• Severe headaches that don't respond to pain medication
• Visual changes including temporary vision loss
• Severe upper abdominal pain
• Shortness of breath or difficulty breathing
• Decreased urination (less than 500ml in 24 hours)
• Confusion or altered mental state
• Severe anxiety or sense of impending doom

HELLP Syndrome Symptoms

HELLP (Hemolysis, Elevated Liver enzymes, Low Platelets) presents with:

• Fatigue and malaise
• Nausea and vomiting
• Upper abdominal pain and tenderness
• Shoulder pain or pain when breathing deeply
• Bleeding or bruising easily
• Jaundice (yellowing of skin or eyes)

Warning Signs of Eclampsia

• Seizures (tonic-clonic)
• Loss of consciousness
• Severe agitation before seizure
• No memory of seizure event
• Postictal confusion

Postpartum Symptoms

Hypertension can develop or worsen after delivery:

• New onset headaches in the first week postpartum
• Visual disturbances after delivery
• Shortness of breath when lying flat
• Swelling that worsens after delivery
• Decreased urination despite adequate fluid intake

Causes

The exact causes of hypertensive disorders in pregnancy remain incompletely understood, but research has identified multiple factors that contribute to their development. The pathophysiology involves complex interactions between maternal, placental, and fetal factors that disrupt normal cardiovascular adaptation to pregnancy.

Placental Factors

The placenta plays a central role in preeclampsia development:

• Abnormal placentation: Shallow trophoblast invasion into maternal spiral arteries
• Placental ischemia: Reduced blood flow leads to oxidative stress
• Release of factors: sFlt-1 and sEng that antagonize VEGF and PlGF
• Inflammatory response: Increased cytokine production
• Endothelial dysfunction: Widespread vascular damage

Maternal Factors

• Immunologic factors: Abnormal maternal immune response to fetal antigens
• Genetic predisposition: Family history increases risk significantly
• Pre-existing vascular disease: Underlying endothelial dysfunction
• Metabolic factors: Insulin resistance, obesity, dyslipidemia
• Inflammatory conditions: Chronic inflammation predisposes to preeclampsia

Types and Their Causes

Gestational Hypertension

• New onset hypertension after 20 weeks
• No proteinuria or other organ dysfunction
• May represent early preeclampsia
• Often resolves postpartum

Preeclampsia

• Multisystem disorder with vascular endothelial damage
• Imbalance of angiogenic and anti-angiogenic factors
• Systemic inflammatory response
• Generalized vasospasm and organ hypoperfusion

Chronic Hypertension

• Pre-existing hypertension before pregnancy
• Hypertension diagnosed before 20 weeks
• May be essential or secondary hypertension
• Risk of superimposed preeclampsia

Pathophysiological Cascade

1. Stage 1: Abnormal placental development (8-18 weeks)
2. Stage 2: Placental stress and factor release (20+ weeks)
3. Stage 3: Maternal syndrome with organ dysfunction
4. Stage 4: Resolution after placental delivery

Contributing Environmental Factors

• Nutritional deficiencies: Low calcium, vitamin D, antioxidants
• Stress: Physical and psychological stress
• Altitude: Higher incidence at high altitudes
• Season: Some seasonal variation noted
• Pollution: Air pollution may increase risk

Risk Factors

Understanding risk factors for hypertensive disorders of pregnancy is crucial for identifying women who need closer monitoring and potentially preventive interventions. Risk factors can be categorized into those present before pregnancy and those that emerge during pregnancy.

Major Risk Factors

• First pregnancy (nulliparity): 3-4 times higher risk
• Previous preeclampsia: 20-30% recurrence risk
• Multiple gestation: Twins triple the risk, higher multiples increase further
• Advanced maternal age: Risk doubles after age 35
• Obesity: Risk increases with BMI; doubles with BMI >30
• Pre-existing hypertension: 25% develop superimposed preeclampsia
• Diabetes: Type 1 or 2, gestational diabetes also increases risk

Medical Conditions

• Kidney disease: Chronic kidney disease or proteinuria
• Autoimmune disorders: Lupus, antiphospholipid syndrome
• Thrombophilias: Inherited or acquired clotting disorders
• Sleep apnea: Increasingly recognized risk factor
• Migraine headaches: Associated with vascular dysfunction
• Polycystic ovary syndrome: Metabolic and vascular effects

Pregnancy-Related Factors

• Assisted reproductive technology: IVF pregnancies at higher risk
• Donor egg/sperm: Immunologic factors may play role
• Long interpregnancy interval: >10 years between pregnancies
• New paternity: Different father than previous pregnancy
• Limited sperm exposure: Barrier contraception use
• Hydatidiform mole: Excessive placental tissue

Family and Genetic Factors

• Family history of preeclampsia: Sister or mother affected
• Paternal factors: Partner born to preeclamptic pregnancy
• Genetic polymorphisms: Various genes identified
• Ethnicity: African American women at higher risk

Lifestyle and Environmental Factors

• High altitude residence: >2500 meters elevation
• Extremes of BMI: Both obesity and being underweight
• Poor nutrition: Low calcium, protein intake
• Stress: Chronic stress or anxiety
• Physical inactivity: Sedentary lifestyle
• Smoking: Paradoxically may reduce risk but not recommended

Risk Stratification

Women can be categorized by risk level:

• High risk: Previous preeclampsia, chronic hypertension, diabetes, kidney disease
• Moderate risk: First pregnancy, age >40, BMI >35, family history
• Low risk: No identified risk factors

Diagnosis

Accurate and timely diagnosis of hypertensive disorders in pregnancy is essential for appropriate management and prevention of complications. Diagnosis relies on blood pressure measurements, laboratory tests, and clinical assessment of symptoms and signs.

Blood Pressure Measurement

• Proper technique: Seated position, appropriate cuff size, rest 5 minutes
• Diagnostic threshold: ≥140 mmHg systolic or ≥90 mmHg diastolic
• Confirmation: Two readings at least 4 hours apart
• Severe hypertension: ≥160/110 mmHg
• Home monitoring: May be used for surveillance
• 24-hour monitoring: Helps identify white coat hypertension

Laboratory Tests

Baseline Tests

• Complete blood count: Assess for thrombocytopenia, hemolysis
• Liver function tests: AST, ALT for liver involvement
• Serum creatinine: Kidney function assessment
• Uric acid: Elevated in preeclampsia
• Lactate dehydrogenase: Marker of hemolysis
• Coagulation studies: If thrombocytopenia present

Proteinuria Assessment

• 24-hour urine collection: Gold standard, ≥300mg/24h significant
• Protein/creatinine ratio: ≥0.3 mg/mg diagnostic
• Urine dipstick: ≥1+ suggestive but needs confirmation
• Not required for diagnosis: New criteria include other organ dysfunction

Diagnostic Criteria

Gestational Hypertension

• New onset BP ≥140/90 after 20 weeks
• No proteinuria
• No other signs of preeclampsia
• Returns to normal by 12 weeks postpartum

Preeclampsia

Hypertension plus one or more of:

• Proteinuria ≥300mg/24h or P/C ratio ≥0.3
• Thrombocytopenia <100,000/μL
• Liver transaminases 2x normal
• Creatinine >1.1 mg/dL or doubling
• Pulmonary edema
• Cerebral or visual symptoms

Preeclampsia with Severe Features

Any of the following:

• BP ≥160/110 on two occasions
• Thrombocytopenia <100,000
• Liver enzyme abnormalities with symptoms
• Progressive renal insufficiency
• Pulmonary edema
• Persistent cerebral symptoms

Fetal Assessment

• Ultrasound: Growth assessment, amniotic fluid volume
• Doppler studies: Umbilical artery, middle cerebral artery
• Non-stress test: Fetal heart rate monitoring
• Biophysical profile: Comprehensive fetal assessment
• Daily fetal movement counts: Patient monitoring

Differential Diagnosis

Conditions that may mimic preeclampsia:

• Acute fatty liver of pregnancy
• Thrombotic thrombocytopenic purpura
• Hemolytic uremic syndrome
• Systemic lupus erythematosus flare
• Chronic kidney disease
• Pheochromocytoma

Treatment Options

Management of hypertension in pregnancy requires balancing maternal health with fetal well-being. Treatment decisions depend on gestational age, severity of hypertension, presence of symptoms, and maternal-fetal status. The definitive treatment for preeclampsia is delivery, but management strategies aim to optimize timing while minimizing risks.

Antihypertensive Medications

First-Line Agents

• Methyldopa:
  • Safest long-term option
  • 250-500mg 2-4 times daily
  • Central acting, well-studied in pregnancy
• Labetalol:
  • Alpha and beta blocker
  • 100-400mg 2-3 times daily
  • Avoid in asthma, heart block
• Nifedipine:
  • Calcium channel blocker
  • 30-120mg daily (extended release)
  • Good for acute and chronic use

Acute Severe Hypertension

• IV Labetalol: 20mg initial, then 40-80mg q10 min
• IV Hydralazine: 5-10mg q20 min
• Immediate-release nifedipine: 10-20mg q30 min
• Goal: Reduce BP to 140-150/90-100 mmHg

Preeclampsia Management

Expectant Management (Before 37 weeks)

• Hospitalization: For severe features or unstable patients
• Daily assessment: Symptoms, BP, fetal monitoring
• Laboratory monitoring: Twice weekly or more
• Corticosteroids: For fetal lung maturity <34 weeks
• Magnesium sulfate: For seizure prophylaxis if severe

Delivery Indications

• Gestational age ≥37 weeks with any preeclampsia
• Gestational age ≥34 weeks with severe features
• Any gestational age with:
  • Eclampsia
  • Uncontrolled severe hypertension
  • Placental abruption
  • Fetal compromise
  • HELLP syndrome

Seizure Prophylaxis

Magnesium Sulfate Protocol

• Loading dose: 4-6g IV over 20 minutes
• Maintenance: 1-2g/hour continuous infusion
• Monitoring:
  • Deep tendon reflexes hourly
  • Urine output (>25ml/hr)
  • Respiratory rate (>12/min)
  • Serum levels if toxicity suspected
• Continue: 24 hours postpartum

Supportive Care

• Fluid management: Avoid overload, maintain 80-100ml/hr
• Pain management: Acetaminophen safe, avoid NSAIDs
• Activity: Modified bed rest not routinely recommended
• Diet: Regular diet, no salt restriction needed
• Monitoring: Input/output, daily weights

Postpartum Management

• BP monitoring: Peak risk days 3-6 postpartum
• Medications:
  • Continue antihypertensives if needed
  • ACE inhibitors/ARBs safe if not breastfeeding
  • Most antihypertensives compatible with breastfeeding
• NSAIDs: Avoid if hypertension, renal dysfunction
• Follow-up: BP check within 7-10 days
• Education: Warning signs, when to seek care

Future Pregnancy Planning

• Preconception counseling: Risk assessment and optimization
• Low-dose aspirin: 81mg daily from 12 weeks
• Calcium supplementation: If dietary intake low
• Early prenatal care: Baseline assessment
• Consider referral: Maternal-fetal medicine specialist

Prevention

While not all cases of hypertensive disorders in pregnancy can be prevented, several evidence-based interventions can reduce risk, particularly in high-risk women. Prevention strategies should begin before conception when possible and continue throughout pregnancy.

Preconception Optimization

• Weight management: Achieve healthy BMI before pregnancy
• Blood pressure control: Optimize with pregnancy-safe medications
• Diabetes management: Achieve good glycemic control
• Medication review: Switch to pregnancy-safe options
• Lifestyle counseling: Diet, exercise, stress management
• Risk assessment: Identify and address modifiable factors

Low-Dose Aspirin

• Recommendation: 81mg daily for high-risk women
• Start timing: Between 12-28 weeks (ideally <16 weeks)
• Continue until: Delivery
• Risk reduction: 10-20% decrease in preeclampsia
• Candidates: Previous preeclampsia, chronic hypertension, diabetes, multiple gestation
• Safety: No increased bleeding risk at low doses

Calcium Supplementation

• Dose: 1-2g daily for women with low intake
• Benefit: Reduces preeclampsia risk by up to 50%
• Most effective: In populations with low dietary calcium
• Start: First trimester or preconception
• Food sources: Encourage dietary calcium first

Lifestyle Modifications

• Regular exercise: 30 minutes moderate activity most days
• Healthy diet: Rich in fruits, vegetables, whole grains
• Stress reduction: Meditation, yoga, counseling
• Adequate sleep: 7-9 hours nightly
• Avoid tobacco: Smoking cessation support
• Limit caffeine: <200mg daily

Nutritional Strategies

• Protein intake: Adequate but not excessive
• Omega-3 fatty acids: May have protective effect
• Antioxidants: Vitamins C and E (studies mixed)
• Folic acid: Standard prenatal supplementation
• Vitamin D: Maintain adequate levels
• Salt: Normal intake, restriction not beneficial

Monitoring and Early Detection

• Regular prenatal care: Early and consistent
• Home BP monitoring: For high-risk women
• Biomarker screening: Research ongoing
• Uterine artery Doppler: May identify high-risk women
• Patient education: Recognition of warning signs

Interventions Under Investigation

• Pravastatin: Promising research for prevention
• Metformin: In obese or diabetic women
• L-arginine: Nitric oxide precursor
• Low molecular weight heparin: In specific populations
• Folic acid supplementation: High doses being studied

When to See a Doctor

Prompt recognition and response to warning signs of hypertensive disorders in pregnancy can be life-saving. Pregnant women should be educated about symptoms requiring immediate medical attention versus those appropriate for routine prenatal visits.

Seek Emergency Care Immediately For:

• Seizures or convulsions
• Severe headache unrelieved by acetaminophen
• Visual changes - seeing spots, flashing lights, or vision loss
• Severe upper abdominal pain, especially right side
• Difficulty breathing or chest pain
• Altered mental state or confusion
• Severe, sudden swelling of face or hands
• Decreased or absent fetal movement
• Vaginal bleeding

Contact Healthcare Provider Same Day For:

• Blood pressure reading ≥140/90 at home
• Persistent headache
• New onset nausea/vomiting in second half of pregnancy
• Significant swelling of hands, face, or feet
• Weight gain >5 pounds in one week
• Pain during pregnancy that's new or worsening
• Persistent heartburn not relieved by antacids
• Decreased urination

Discuss at Next Prenatal Visit:

• Mild swelling of feet and ankles
• Occasional headaches responding to rest/hydration
• Questions about risk factors or prevention
• Family history of preeclampsia
• Concerns about blood pressure readings
• Problems during pregnancy that are mild/intermittent

Postpartum Warning Signs (First 6 Weeks):

• Severe headache
• Vision changes
• Shortness of breath when lying flat
• Pain in upper abdomen
• Swelling that's new or worsening
• Blood pressure ≥140/90
• Seizures

Follow-up Care Requirements:

• Blood pressure check 7-10 days postpartum
• 6-week postpartum comprehensive evaluation
• 3-6 month cardiovascular risk assessment
• Annual blood pressure screening lifelong
• Preconception counseling for future pregnancies

Related Conditions

Hypertensive disorders of pregnancy are associated with various other conditions, both during pregnancy and long-term. Understanding these relationships helps in comprehensive management and follow-up care.

Pregnancy Complications

• Gestational diabetes - Shared metabolic risk factors
• Placental abruption - Premature placental separation
• Intrauterine growth restriction - Poor placental function
• Preterm labor - Often iatrogenic for maternal/fetal health
• HELLP syndrome - Severe variant of preeclampsia
• Acute fatty liver of pregnancy - Can mimic preeclampsia

Long-term Cardiovascular Risks

• Chronic hypertension - 4-fold increased risk
• Coronary artery disease - 2-fold increased risk
• Stroke - Increased risk, especially younger women
• Heart failure - Related to diastolic dysfunction
• Peripheral artery disease - Vascular dysfunction

Metabolic Conditions

• Type 2 diabetes - 3-4 fold increased risk
• Metabolic syndrome - Insulin resistance
• Dyslipidemia - Abnormal cholesterol levels
• Obesity - Both risk factor and consequence

Kidney Disease

• Chronic kidney disease - Especially after severe preeclampsia
• Persistent proteinuria - May continue postpartum
• Glomerulonephritis - Can be unmasked by pregnancy
• Kidney stones - Increased risk with metabolic changes

Neurological Conditions

• Migraine headaches - May worsen or improve
• Epilepsy - Must distinguish from eclampsia
• PRES - Posterior reversible encephalopathy syndrome
• Cerebral venous thrombosis - Rare but serious

Autoimmune Conditions

• Lupus - Can flare during pregnancy
• Antiphospholipid syndrome - Increases preeclampsia risk
• Rheumatoid arthritis - May improve during pregnancy
• Thyroid disorders - Can affect blood pressure

Frequently Asked Questions

References

1. American College of Obstetricians and Gynecologists. Gestational Hypertension and Preeclampsia: ACOG Practice Bulletin No. 222. Obstet Gynecol. 2020;135(6):e237-e260.
2. Magee LA, et al. The 2021 International Society for the Study of Hypertension in Pregnancy classification, diagnosis & management recommendations for international practice. Pregnancy Hypertens. 2022;27:148-169.
3. Webster K, et al. Diagnosis and management of hypertension in pregnancy: summary of updated NICE guidance. BMJ. 2019;366:l5119.
4. Brown MA, et al. Hypertensive Disorders of Pregnancy: ISSHP Classification, Diagnosis, and Management Recommendations for International Practice. Hypertension. 2018;72(1):24-43.
5. US Preventive Services Task Force. Aspirin Use to Prevent Preeclampsia and Related Morbidity and Mortality: US Preventive Services Task Force Recommendation Statement. JAMA. 2021;326(12):1186-1191.
6. Rana S, et al. Preeclampsia: Pathophysiology, Challenges, and Perspectives. Circ Res. 2019;124(7):1094-1112.