Worst outcomes if missed
- Death - pre-eclampsia is the second most common direct cause of maternal death in the UK. The major risk of severe hypertension from pre-eclampsia is cerebral haemorrhage, a cause of maternal death that is preventable by prompt referral to obstetric care.
- Neonatal morbidity and mortality - growth restriction and iatrogenic pre-term delivery are significant causes of neonatal morbidity and mortality in the UK.
Epidemiology
- Pre-eclampsia is a multi-system disorder with complex aetiology, which is associated with poor placental perfusion and an exaggerated maternal immune response.
- It affects 2-3% of pregnancies overall and one in 200 pregnancies severely.
Symptoms and signs
Symptoms of pre-eclampsia can include severe headache, visual disturbance, upper abdominal pain, nausea, vomiting, and reduced or absent foetal movements.
New hypertension on its own is the most common first symptom of evolving pre-eclampsia. But in 10% of cases the first sign is proteinuria on its own.
Women can present with signs and symptoms of pre-eclampsia anytime from 20 weeks of pregnancy to 23 days after delivery.
In its early stages, pre-eclampsia has no symptoms. It is most commonly picked up through routine blood pressure and urine screening. Raised blood pressure can be mild (140/90mmHg to 144/99mmHg), moderate (150/100mmHg to 159/100mmHg) or severe (160/110mmHg or above).
In the mother, pre-eclampsia can cause raised blood pressure, deranged clotting, and liver and kidney problems. Eclampsia (seizures) and HELLP syndrome (haemolysis, elevated liver enzymes, low platelets) are recognised complications. Babies of mothers with pre-eclampsia are at risk of intrauterine growth restriction, placental abruption and stillbirth.
After the baby has been delivered the woman’s blood pressure typically falls initially and then increases again around three to five days after delivery.
Around 42% of eclamptic fits occur after delivery and most women with a diagnosis of pre-eclampsia will remain in hospital for up to five days postnatally to ensure that their blood pressure is well controlled and that any biochemical abnormalities are returning to normal.
A proportion of women with pre-eclampsia will develop chronic hypertension requiring medication postnatally. But all women who develop pre-eclampsia in pregnancy have an increased risk of developing hypertension in later years.
Differential diagnosis
Pregnancy-induced hypertension – new-onset hypertension in pregnancy in the absence of proteinuria -requires immediate referral to hospital obstetric-led management of hypertension because it could be a sign of evolving pre-eclampsia.
Proteinuria in the absence of raised blood pressure can be associated with urinary tract infections and vaginal discharge. If the blood pressure is within the normal range, ask the woman about symptoms of UTI and discharge and send the urine for MSU. If there are no symptoms and the MSU is normal, but the woman has persistent proteinuria, refer to obstetric care for further assessment.
Investigations and referral
Antenatal care focuses on recognition of risk factors for pre-eclampsia, and routine monitoring of blood pressure and urine. Women with pre-eclampsia can become unwell very quickly.
All pregnant women who are found to have more than 1+ of protein in their urine and blood pressure higher than 145/95mmHg (or more than 30mmHg over their booking blood pressure) should be referred to hospital for immediate obstetric assessment. If the diagnosis of pre-eclampsia is made, these women will to be managed as inpatients until delivery.
Some women are at increased risk of pre-eclampsia. The box below lists risk factors and patients with the conditions highlighted in bold may benefit from early referral to an obstetrician for consideration of calcium supplements and low-dose aspirin, which have been shown to reduce the risk of pre-eclampsia.
Risk factors for pre-eclampsia
- Extremes of maternal age - teenagers, women over 40
- First pregnancy
- Gap of more than 10 years since last pregnancy
- Pregnancies conceived through assisted reproduction techniques
- BMI of more than 35
- Family history of pre-eclampsia
- Multiple pregnancies
- Women with a history of pre-eclampsia
- Women with chronic kidney disease
- Women with diabetes
- Women with antiphospholipid antibodies
During pregnancy, hypertension above the threshold specified by the NICE guidelines (>150/100mmHg) is managed with labetalol, methyldopa, which are known to be safe in pregnancy.1 ACE inhibitors and ARBs are contraindicated.
Follow-up
Women discharged from hospital on antihypertensive medication should be seen by their GP in the immediate postnatal period to assess whether they still require medication. Around 50-85% of these women will have blood pressures within normal range at seven days post-delivery, and they can stop taking antihypertensives. Any persistent hypertension or proteinuria at the six-week postnatal check requires further investigation.
One of the most challenging aspects in the management of pre-eclampsia is the emotional impact that the condition can have. Anger, grief, fear and uncertainty are common. It is not surprising that women who have had pre-eclampsia are at higher risk of postnatal depression.
Women who have had one pregnancy complicated by pre-eclampsia are often anxious to know if future pregnancies will be affected and how they will be cared for in those pregnancies. The overall risk of developing pre-eclampsia in a future pregnancy is one in six. This increases to about one in four if they had severe pre-eclampsia, HELLP syndrome or eclampsia, or the pre-eclampsia led to birth before 34 weeks. Risk increases to about one in two if it led to birth before 28 weeks. The recurrence rate of HELLP syndrome itself is about 1-3%
It is important to refer women who have had early-onset or severe pre-eclampsia for hospital-based care in future pregnancies.
Five key questions to ask
- Is there a family or personal history of pre-eclampsia?
- Has the woman experienced headache or visual disturbance
- Is there any epigastric pain?
- Is there facial oedema?
- Has the woman noticed a reduction or absence of foetal movements?
Five red herrings
- Don’t be falsely reassured if a woman with proteinuria and hypertension reports symptoms of UTI (or an MSU is positive) because pre-eclampsia and UTI can co-exist.
- Hypertension might not be a feature in early pre-eclampsia, so don’t delay referral for any woman who has significant proteinuria, even if blood pressure is normal
- Remember to consider the booking blood pressure when assessing a borderline blood pressure with proteinuria. A blood pressure of 140/80 may not seem that high, but it is a significant rise if the booking blood pressure was 98/58, for example’
- Symptoms of pre-eclampsia can start sooner or later than is generally supposed – from 20 weeks of pregnancy to 23 days after delivery.
- Do not be misled by the absence of symptoms – pre-eclampsia may have no symptoms at all in the early stages.
Professor Catherine Nelson-Piercy is a consultant obstetric physician at Guy’s and St Thomas’ Hospitals Trust and Queen Charlotte’s and Chelsea Hospital in London.
Dr Kim Turner is an obstetrics and gynaecology specialty trainee in the Northwest Thames Deanery.
Professor Catherine Nelson-Piercy and Dr Kim Turner are trustees of Action on Pre-eclampsia, a UK charity which aims to raise awareness of pre-eclampsia among the public and professionals, to inform and support women and their families and to campaign for more research into this devastating condition. Action on Pre-eclampsia periodically run study days for midwives and other professionals involved in the care of pregnant women, including GPs, and hold an annual meeting bringing together the leading experts in the UK to discuss the latest developments in research and treatment. For more information click here, email info@apec.org.uk or call the helpline on 0208 427 4217.
