Definition:
Pre-eclampsia is a pregnancy-specific syndrome characterized by new-onset hypertension (blood pressure ā„ 140/90 mmHg on two occasions at least 4 hours apart after 20 weeks of gestation) and either proteinuria or significant end-organ dysfunction. It is a multisystem progressive disorder considered a spectrum that can progress to eclampsia, a severe complication involving seizures.
Epidemiology:
- Affects 2-8% of pregnancies worldwide.
- Higher prevalence in nulliparous women, teenage pregnancies, and pregnancies in women over 40.
Risk Factors:
- First pregnancy (nulliparity)
- History of pre-eclampsia
- Family history of pre-eclampsia
- Pre-existing medical conditions (e.g., hypertension, diabetes, kidney disease)
- Multiple gestation (e.g., twins or triplets)
- Obesity
- Advanced maternal age (>40 years)
- In vitro fertilization (IVF) pregnancies
Pathophysiology:
- The exact cause of pre-eclampsia remains unclear, but it is believed to involve abnormal placental development and function leading to systemic endothelial dysfunction.
- Insufficient trophoblastic invasion of the spiral arteries results in reduced placental perfusion and hypoxia, contributing to the release of antiangiogenic factors into the maternal circulation, causing endothelial dysfunction and the clinical manifestations of pre-eclampsia.
Clinical Features
Signs and Symptoms:
- Hypertension
- Proteinuria
- Swelling (edema), particularly in the hands and face
- Sudden weight gain over 1-2 days
- Severe headaches
- Visual disturbances (e.g., blurred vision, light sensitivity)
- Upper abdominal pain (especially right upper quadrant or epigastric)
- Nausea or vomiting
- Decreased urine output
Diagnosis:
- Blood pressure measurement ā„ 140/90 mmHg on two separate occasions
- Proteinuria ā„ 300 mg in a 24-hour urine collection or a protein/creatinine ratio ā„ 0.3
- In the absence of proteinuria, diagnosis can be based on new-onset hypertension with significant end-organ dysfunction (e.g., renal insufficiency, liver involvement, neurological features, hematological complications, or uteroplacental dysfunction)
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Management
Antepartum Management:
- Close monitoring of blood pressure, urine protein levels, and fetal well-being.
- Antihypertensive therapy to control severe hypertension.
- Corticosteroids for fetal lung maturity if delivery is anticipated before 34 weeks of gestation.
- Consideration of low-dose aspirin starting in the first trimester for those at high risk.
Timing of Delivery:
- The definitive treatment for pre-eclampsia is delivery of the placenta. The timing depends on the severity of the condition, gestational age, and fetal condition:
- After 37 weeks: prompt delivery is recommended.
- Between 34-37 weeks: delivery is recommended for women with gestational hypertension or mild pre-eclampsia.
- Before 34 weeks: management depends on the severity of pre-eclampsia and fetal conditions, with an aim to prolong pregnancy as long as it is safe.
Intrapartum and Postpartum Care:
- Magnesium sulfate for seizure prophylaxis in severe cases.
- Continuous fetal and maternal monitoring.
- Postpartum monitoring, as pre-eclampsia can persist or even manifest after delivery.
Complications
- Eclampsia (seizures)
- HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelet count)
- Placental abruption
- Acute renal failure
- Liver hematoma or rupture
- Disseminated intravascular coagulation (DIC)
- Cerebral hemorrhage
- Cardiovascular complications
- Fetal growth restriction, preterm birth, and stillbirth
Summary
Pre-eclampsia is a complex, multi-system disorder that significantly impacts maternal and fetal health. Early detection, close monitoring, and timely intervention are crucial to manage pre-eclampsia effectively and prevent progression to more severe complications. Understanding the risk factors, pathophysiology, clinical manifestations, and management strategies for pre-eclampsia is essential for medical students and healthcare professionals involved in obstetric care.
