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.