Pre-eclampsia and Eclampsia

Eclampsia is defined as the occurrence of one or more convulsions superimposed on pre-eclampsia.

Pre-eclampsia is pregnancy-induced hypertension in association with proteinuria (> 0.3 g in 24 hours) with or without oedema. Virtually any organ system may be affected.

In women with severe pre-eclampsia, diastolic blood pressure is 110 mmHg or higher on two occasions, or systolic blood pressure 170 mmHg or greater on two occasions, associated with significant proteinuria.¹ Pre-eclampsia is a major cause of poor pregnancy outcome including maternal and fetal mortality and severe obstetric morbidity.²

• Severe pre-eclampsia and eclampsia are relatively rare but serious complications of pregnancy. The incidence of severe pre-eclampsia is about 5/1000 maternities.¹ The incidence of eclampsia in the UK is 4.9/10,000 maternities.³
• Forty-four percent of seizures occur postnatally, the remainder being antepartum (38%) or intrapartum (18%).

Risk Factors

• Factors that can be measured early in pregnancy that increase the likelihood of pre-eclampsia developing in any given pregnancy:⁴
• First pregnancy, or first pregnancy with new partner
• Multiparous with:
  • Pre-eclampsia in any previous pregnancy
  • Ten years or more since last baby
• Age 40 years or more
• Body Mass Index of 35 or more
• Family history of pre-eclampsia (in mother or sister)
• Booking diastolic blood pressure of 80mmHg or more
• Booking proteinuria (of 1 or more, on more than one occasion or quantified at 0.3g/ 24 hr or greater)
• Multiple pregnancy
• Certain underlying medical conditions:
  • Pre-existing hypertension
  • Pre-existing renal disease
  • Pre-existing diabetes
  • Antiphospholipid antibodies

• New hypertension
• New and/or significant proteinuria
• Other clinical features of severe pre-eclampsia include:
  • Severe headache - usually frontal
  • Liver tenderness
  • Visual disturbance
  • Platelet count falling to below 100 x 10⁶/l
  • Epigastric pain and/or vomiting
  • Abnormal liver enzymes (ALT or AST rising to above 70 iu/l)
  • Clonus
  • HELLP syndrome: H (haemolysis) EL (elevated liver enzymes) LP (low platelets).
  • Papilloedema
  • Fetal distress - reduced fetal movements
  • Small for gestational age infant

Blood pressure measurement

• Use sitting or semi-reclining position so that the arm to be used is at the level of the heart.
• Do not take the blood pressure in the upper arm with the woman on her side as this will give falsely lower readings.

Usually performed in secondary care:

• Fetal monitoring.
• Urinalysis: send for microscopy, culture and sensitivities if proteinuria present.
• Frequent monitoring of full blood count, liver function tests, renal function, electrolytes and serum urate: to identify rising values to help guide the decision as to when to deliver.
• Clotting studies if severe pre-eclampsia or thrombocytopenia.
• 24-hour urine collections for protein quantification and creatinine clearance.
• Cerebral imaging (MRI or CT) is not indicated in uncomplicated eclampsia. However, imaging is necessary to exclude haemorrhage and other serious abnormalities in women with focal neurological deficits or prolonged coma.

• Management in hospital is multidisciplinary with involvement of the obstetric team, anaesthetics and haematology, liaison with paediatrics, and appropriate arrangements for in-utero transfer if required and once the women's condition is stable.
• Mean arterial blood pressure is monitored on some labour wards, as a more accurate measure than diastolic blood pressure.

Frequency of community monitoring

• No predisposing factors for pre-eclampsia: 24 weeks gestation to delivery: follow local protocols and NICE antenatal guideline for low risk multiparous women.⁵
• One predisposing factor listed above, but no factor that requires referral in early pregnancy (listed below):
  • 24 to 32 weeks gestation: Minimum standard no more than 3 week interval between assessments, adjusted to individual needs and any changes during pregnancy.
  • 32 weeks gestation to delivery: Minimum standard no more than 2 week interval between assessments, adjusted to individuals needs and any changes during pregnancy.

All pregnant women should be aware that after 20 weeks gestation pre-eclampsia may develop between antenatal assessments, and that it is appropriate for them to self-refer at any time. Offer pregnant women with the following predisposing factors for pre-eclampsia early referral in pregnancy for specialist input to their antenatal care plan:

• Multiple pregnancy
• Underlying medical conditions:
  • Pre-existing hypertension or booking diastolic BP 90 mmHg or above
  • Pre-existing renal disease or booking proteinuria (1 or more, on more than one occasion or quantified at 0.3g/ 24 hour or greater)
  • Pre-existing diabetes
  • Antiphospholipid antibodies
• Pre-eclampsia in any previous pregnancy
• Any two other pre-disposing factors from the risk factors listed above, i.e. first pregnancy, age 40 years or more, BMI 35 or greater, family history, booking diastolic BP between 80 and 89 mmHg.

Community monitoring: thresholds for further action

• New hypertension without proteinuria after 20 weeks:
  • Diastolic BP 90-99mmHg: refer for hospital assessment within 48 hours.
  • Diastolic BP 90-99mmHg with significant symptoms (epigastric pain, vomiting, headache, visual disturbances, reduced fetal movements, small for gestational age infant): refer for same day hospital assessment.
  • Systolic BP 160mmHg or greater: refer for same day hospital assessment.
  • Diastolic BP 100mmHg or greater: refer for same day hospital assessment.
• New hypertension and proteinuria after 20 weeks:
  • Diastolic BP 90mmHg or greater, and new proteinuria 1 or greater on dipstick: refer for same day hospital assessment.
  • Diastolic BP 110mmHg or greater, and new proteinuria 1 or greater on dipstick: arrange immediate admission.
  • Systolic BP 170mmHg or greater, and new proteinuria 1 or greater on dipstick: arrange immediate admission.
  • Diastolic BP 90mmHg or greater, and new proteinuria 1 or greater on dipstick and significant symptoms (epigastric pain, vomiting, headache, visual disturbances, reduced fetal movements, small for gestational age infant): arrange immediate admission.
• New proteinuria without hypertension after 20 weeks:
  • 1on dipstick: repeat pre-eclampsia assessment in community within 1 week.
  • 2 or more on dipstick: refer for hospital assessment within 48 hours.
  • New proteinuria without hypertension after 20 weeks: 1 or greater on dipstick with significant symptoms (epigastric pain, vomiting, headache, visual disturbances, reduced fetal movements, small for gestational age infant): refer for same day hospital assessment.
• Maternal symptoms or fetal signs and symptoms without new hypertension or proteinuria:
  • Headache and or visual disturbances with diastolic blood pressure less than 90mmHg and a trace or no protein: follow local protocols for investigation. Consider reducing the interval before the next assessment.
  • Epigastric pain with diastolic blood pressure less than 90mmHg and a trace or no protein: refer for same day hospital assessment.
  • Reduced movements or small for gestational age infant with diastolic blood pressure less than 90mmHg and a trace or no protein: follow local protocols for investigation of fetal compromise. Consider reducing interval before next full pre-eclampsia assessment.

• Blood pressure:
  • Antihypertensive treatment should be started in women with a systolic blood pressure over 160 mmHg or a diastolic blood pressure over 110 mmHg. In women with other markers of potentially severe disease, treatment can be considered at lower degrees of hypertension.
  • Labetalol (given orally or intravenously), oral nifedipine or intravenous hydralazine can be used for the acute management of severe hypertension.
  • Atenolol, ACE inhibitors, angiotensin receptor-blockers and diuretics should be avoided.
  • Anti-hypertensive medication should be continued after delivery as dictated by the blood pressure. It may be necessary to maintain treatment for up to 3 months, although most women can have treatment stopped before this.
• Prevention of seizures:
  • Magnesium sulphate should be considered when there is concern about the risk of eclampsia.
  • In women with less severe disease, the decision is less clear and will depend on individual case assessment.
• Control of seizures:
  • Magnesium sulphate is the therapy of choice to control seizures. A loading dose of 4 g is given by infusion pump over 5-10 minutes, followed by a further infusion of 1 g/hour maintained for 24 hours after the last seizure.
  • Recurrent seizures should be treated with either a further bolus of 2 g magnesium sulphate or an increase in the infusion rate to 1.5 g or 2.0 g/hour.
• Fluid balance:
  • Fluid restriction is advisable to reduce the risk of fluid overload in the intrapartum and postpartum periods. Total fluids should usually be limited to 80 ml/hour or 1 ml/kg/hour.
• Delivery:
  • The decision to deliver should be made once the woman is stable and with appropriate senior personnel present.
  • If the fetus is less than 34 weeks of gestation and delivery can be deferred, corticosteroids should be given, although after 24 hours the benefits of conservative management should be reassessed.
  • Conservative management at very early gestations may improve the perinatal outcome but must be carefully balanced with maternal wellbeing.
  • The mode of delivery should be determined after considering the presentation of the fetus and the fetal condition, together with the likelihood of success of induction of labour after assessment of the cervix.
  • The third stage should be managed with 5 units intramuscular/slow intravenous Syntocinon. Ergometrine and Syntometrine should not be given for prevention of haemorrhage, as this can further increase the blood pressure.

• Resuscitation. The patient should be placed in the left lateral position and the airway secured. Oxygen should be administered.
• Treatment and prophylaxis of seizures:
  • Magnesium sulphate: more than halves the risk of eclampsia, and probably reduces the risk of maternal death. It does not improve the outcome for the baby. Magnesium sulphate appears to be substantially more effective than diazepam or phenytoin for the treatment of eclampsia.⁶
  • Other treatments: if repeated seizures occur despite magnesium, options include diazepam (10mg IV) or thiopentone (50mg IV). Intubation may become necessary in such women in order to protect the airway and ensure adequate oxygenation. Further seizures should be managed by intermittent positive pressure ventilation and muscle relaxation.
• Treatment of hypertension:
  • Reduction of severe hypertension (blood pressure >160/110 mm Hg or mean arterial pressure >125 mm Hg) is essential to reduce the risk of cerebrovascular accident. Treatment may also reduce the risk of further seizures.
  • Intravenous hydralazine or labetalol are the two most commonly used drugs. Both may precipitate fetal distress and therefore continuous fetal heart rate monitoring is necessary.
• Fluid therapy:
  • Close monitoring of fluid intake and urine output is mandatory.
  • Pre-loading the circulation with 400-500ml colloid prior to regional anaesthesia or vasodilatation with hydralazine may reduce the risk of hypotension and fetal distress.
• Delivery:
  • The definitive treatment of eclampsia is delivery. Attempts to prolong pregnancy in order to improve fetal maturity are unlikely to be of value.
  • However, it is inappropriate to deliver an unstable mother even if there is fetal distress. Once seizures are controlled, severe hypertension treated, and hypoxia corrected, delivery can be expedited.
  • Vaginal delivery should be considered but caesarean section is likely to be required in primigravidae, well before term and with an unfavourable cervix.
  • After delivery, high dependency care should be continued for a minimum of 24 hours.

• Eclampsia is usually part of a multisystem disorder. Associated complications include haemolysis, elevated liver enzymes and low platelets (HELLP) syndrome (3%), disseminated intravascular coagulation (3%), renal failure (4%) and adult respiratory distress syndrome (3%).
• HELLP syndrome: H (haemolysis) EL (elevated liver enzymes) LP (low platelets). This syndrome can occur in severe pre-eclampsia, may present with epigastric pain and may be life-threatening. Hepatocellular dysfunction may lead to necrosis and swelling.
• Neurological complications of eclampsia include coma, focal motor deficits and cortical blindness. Cerebrovascular haemorrhage is a complicating factor in 1-2%.

• Pre-eclampsia is also associated with fetal growth restriction, low birth weight, preterm delivery, small for gestational age infants and respiratory distress syndrome.
• The maternal mortality rate of eclampsia is 1.8%.
• 35% of women with eclampsia will have at least one major complication.⁷

• Identification and appropriate action for those women with known risk factors at booking.
• Early recognition and appropriate action for those women with symptoms and signs of pre-eclampsia.
• Antiplatelet agents, e.g. low-dose aspirin, have moderate benefits when used for prevention of pre-eclampsia.⁸