Definitions

• Hypertension in pregnancy is defined as a diastolic BP > 90 mmHg and/or systolic BP > 140 mmHg.
• Severe hypertension is defined as diastolic BP > 110 mmHg and/or systolic blood pressure > 160 mmHg.
• Gestational hypertension is new hypertension presenting after 20 weeks’ gestation without significant proteinuria.
• Pre-eclampsia is new hypertension presenting after 20 weeks gestation and the coexistence of 1 or more of the following new-onset conditions:
  • Proteinuria
  • Other maternal organ dysfunction:
    • Renal insufficiency (creatinine 90 micromol/litre or more, 1.02 mg/100 ml or more).
    • Liver involvement (elevated transaminases [alanine aminotransferase or aspartate aminotransferase over 40 IU/litre] with or without right upper quadrant or epigastric abdominal pain).
    • Neurological complications such as eclampsia, altered mental status, blindness, stroke, clonus, severe headaches or persistent visual scotomata.
    • Haematological complications such as thrombocytopenia (platelet count below 150,000/microlitre), disseminated intravascular coagulation or haemolysis
    • Uteroplacental dysfunction such as fetal growth restriction, abnormal umbilical artery doppler waveform analysis, or stillbirth.
• HELLP syndrome (Haemolysis, Elevated Liver enzymes, and Low Platelets syndrome) is a severe form of pre-eclampsia that is associated with high maternal and perinatal morbidity and mortality.
• Eclampsia is the occurrence of one or more seizures in a woman with pre-eclampsia.

Risk factors

Women are at high-risk of pre-eclampsia if they have:

• One of the following high risk factors
  • A history of hypertensive disease during a previous pregnancy
  • Chronic kidney disease
  • Autoimmune disease, such as systemic lupus erythematosus or antiphospholipid syndrome
  • Type 1 or type 2 diabetes
  • Chronic hypertension
• Two or more of the following moderate risk factors:
  • First pregnancy
  • Aged 40 years or older
  • Pregnancy interval of more than 10 years
  • Body mass index (BMI) of 35 kg/m2 or greater at the first visit
  • Family history of pre-eclampsia
  • Multiple pregnancy

Clinical features

Symptoms of pre-eclampsia

• Severe headaches (increasing frequency unrelieved by regular analgesics).
• Visual problems, such as blurred vision, flashing lights, double vision, or floating spots.
• Persistent new epigastric pain or pain in the right upper quadrant.
• Vomiting.
• Breathlessness.
• Sudden swelling of the face, hands, or feet.

Complications

Pre-eclampsia is a multi-system disorder that is associated with significant maternal morbidity.

Complications of pre-eclampsia include:

• Maternal complications
  • Eclamptic seizures
  • Acute renal failure
  • Liver dysfunction
  • Coagulation abnormalities
  • Intracranial haemorrhage
  • Cerebral infarction
  • Cerebral oedema
  • Acute respiratory distress syndrome and pulmonary oedema
  • Hepatic rupture and hepatic failure/necrosis
  • Death
• Fetal complications
  • Placental abruption
  • IUGR
  • Preterm delivery
  • Stillbirth
  • Neonatal death

Management

• For women assessed to be at high risk of pre-eclampsia, aspirin 75 - 150 mg daily is prescribed from 12 weeks gestation until birth.
• For all pregnant women, dipstick the urine for protein and measure blood pressure at each visit.
  • If dipstick screening is positive [1+ or more], use albumin:creatinine ratio or protein:creatinine ratio to quantify proteinuria in pregnant women.
  • If using protein:creatinine ratio, use 30 mg/mmol as a threshold for significant proteinuria.
  • If using albumin:creatinine ratio, use 8 mg/mmol as a diagnostic threshold.
• Assess for symptoms of pre-eclampsia at each visit. Advise the woman that she should seek immediate medical review if she develops any symptoms (including during the first four weeks postpartum).
• If BP 140/90–159/109 mmHg in pre-eclampsia
  • Admit if any clinical concerns for the wellbeing of the woman or baby or if high risk of adverse events suggested by the fullPIERS or PREP‑S risk prediction models
  • Offer pharmacological treatment if BP remains above 140/90 mmHg
  • Aim for BP of 135/85 mmHg or less
  • BP should be measured at least every 48 hours, and more frequently if the woman is admitted to hospital
  • Measure full blood count, liver function and renal function twice a week
• If BP 160/110 mmHg or more in pre-eclampsia
  • Admit
  • Offer pharmacological treatment to all women
  • Aim for BP of 135/85 mmHg or less
  • BP should be measured every 15–30 minutes until BP is less than 160/110 mmHg, then at least 4 times daily while the woman is an inpatient, depending on clinical circumstances
  • Measure full blood count, liver function and renal function 3 times a week
• Choice of antihypertensive
  • Offer labetalol to treat hypertension in pregnant women with pre-eclampsia.
  • Offer nifedipine for women in whom labetalol is not suitable, and methyldopa if labetalol or nifedipine are not suitable.
  • Base the choice on any pre-existing treatment, side-effect profiles, risks (including fetal effects) and the woman's preference.
  • Treat women with severe hypertension who are in critical care during pregnancy or after birth immediately with 1 of the following:
    • labetalol (oral or intravenous)
    • oral nifedipine
    • intravenous hydralazine
• Anticonvulsants
  • If a woman in a critical care setting who has severe hypertension or severe pre-eclampsia has or previously had an eclamptic fit, give intravenous magnesium sulfate.
  • Consider giving intravenous magnesium sulfate to women with severe pre-eclampsia who are in a critical care setting if birth is planned within 24 hours.
  • Consider the need for magnesium sulfate treatment, if 1 or more of the following features of severe pre-eclampsia is present:
    • ongoing or recurring severe headaches
    • visual scotomata
    • nausea or vomiting
    • epigastric pain
    • oliguria and severe hypertension
    • progressive deterioration in laboratory blood tests (such as rising creatinine or liver transaminases, or falling platelet count)
  • A loading dose of 4 g should be given intravenously over 5 to 15 minutes, followed by an infusion of 1 g/hour maintained for 24 hours. If the woman has had an eclamptic fit, the infusion should be continued for 24 hours after the last fit.
  • Recurrent fits should be treated with a further dose of 2–4 g given intravenously over 5 to 15 minutes.
  • Do not use diazepam, phenytoin or other anticonvulsants as an alternative to magnesium sulfate in women with eclampsia.