Pre-eclampsia - NYSORA

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Learning objectives

  • Definition and signs and symptoms of pre-eclampsia
  • Management of pre-eclampsia

Definition and mechanisms

  • Pre-eclampsia is defined as new onset hypertension (systolic blood pressure ≥ 140 mmHg, diastolic blood pressure ≥ 90 mmHg, or both) accompanied by one or more of the following features at or after 20 weeks of gestation:
    • Proteinuria:
      • Spot urinary protein creatinine ratio > 30 mg/mmol 
      • Or a 24-hour urine collection with > 300 mg of protein
    • Other material organ dysfunction, including:
      • Acute kidney injury
      • Liver involvement
      • Neurological complications: seizures, severe headaches, persistent visual scotomata, clonus, blindness, altered mental status, or stroke
    • Hematological complications: 
  • Pre-eclampsia can be superimposed on women who have hypertension or proteinuria before 20 weeks of gestation and diagnosis can be more problematic in these patients
  • Pre-eclampsia represents a potentially progressive clinical condition and the sub-categories ‘mild’ and ‘severe’ are no longer used
  • HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome is potentially life-threatening to both mother and the baby and represents a severe form of pre-eclampsia
  • Women may be critically unwell at presentation with placental abruption or DIC
  • Left untreated, preeclampsia can lead to serious — even fatal — complications for both the mother and baby
    • Early delivery of the baby is often recommended 
  • Pre-eclampsia affects 2–8% of pregnancies worldwide

Signs and symptoms

  • Proteinuria or other signs of kidney problems
  • Thrombocytopenia
  • Increased liver enzymes 
  • Severe headaches
  • Changes in vision, including temporary loss of vision, blurred vision, or light sensitivity
  • Shortness of breath
  • Abdominal pain
  • Nausea or vomiting

Severe pre-eclampsia

  • Severe features associated with pre-eclampsia that warrant consideration of planned early birth before 37 weeks of gestation:
    • Inability to control maternal blood pressure despite using 3 or more classes of antihypertensives in appropriate doses
    • Progressive deterioration in liver function, renal function, hemolysis, or platelet count
    • Maternal pulse oximetry less than 90% on air
    • Ongoing neurological features, such as severe intractable headache, repeated visual scotomata, or eclampsia
    • Placental abruption
    • Reversed end-diastolic flow in the umbilical artery Doppler velocimetry, a non-reassuring cardiotocograph or stillbirth


  • Abnormal placentation
  • Immunological factors
  • Prior or existing maternal pathology (see risk factors)
  • Dietary actors such as low dietary calcium intake
  • Environmental factors such as air pollution

Risk factors

High risk factorsModerate risk factors
Hypertensive disease in previous pregnancy
Chronic kidney disease
Autoimmune disease (e.g. antiphospholipid syndrome)
Type 1 or type 2 diabetes mellitus
Chronic Hypertension
First pregnancy
Age≥40 years
Pregnancy interval≥10 yr
Family history of pre-eclampsia
Multiple pregnancy


  • Daily intake of 75-150 mg aspirin from 12 weeks until 36-37 weeks of gestation for any woman with one high, or two or more moderate risk factors
  • Calcium supplementation (> 1 g/day) in case of low calcium dietary intake


  • Blood pressure ≥ 140 mmHg systolic or ≥ 90 mmHg diastolic on two separate readings taken at least four to six hours apart after 20 weeks of gestation in an individual with previously normal blood pressure
  • An increase in systolic blood pressure of ≥ 30 mmHg or an increase in diastolic blood pressure of ≥ 15 mmHg in a woman with essential hypertension beginning before 20 weeks of gestational age
  • Proteinuria ≥ 0.3 grams (300 mg) or more of protein in a 24-hour urine sample or a SPOT urinary protein to creatinine ratio ≥ 0.3
  • Blood and urine analysis
  • Fetal ultrasound


pre-operative management of pre-eclampsia, labetalol, nifedipine, methyldopa, hypertension, hydralazine, gylcerol trinitrate, magnesium sulphate, calcium gluconate, hemolysis, aspartate transaminase, alanine transaminase, gamma-glutamyltransferase, thrombocytopenia, proteinuria

Operative management of pre-eclampsia, phenylephrine, ephedrine, alfentanil, remifentanil, esmolol, labetalol, magnesium sulphate, airway edema, postpartum hemorrhage, oxytocin, carboprost, misoprostol, central venous pressure

Suggested reading

  • Goddard, J., Wee, M.Y.K., Vinayakarao, L., 2020. Update on hypertensive disorders in pregnancy. BJA Education 20, 411–416.
  • Leslie, D., Collis, R., 2016. Hypertension in pregnancy. BJA Education 16, 33–37.

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