Pre-eclampsia testing in London

Pre-eclampsia is a pregnancy complication characterised by high blood pressure (hypertension) and signs of damage to other organ systems, most commonly affecting the liver and kidneys. It typically develops after 20 weeks of pregnancy and occurs when the placenta doesn’t develop properly, leading to problems with the blood vessels that supply it. This causes the release of certain substances into the mother’s bloodstream that affect blood vessel function throughout the body, resulting in high blood pressure and potential complications for both mother and baby.

The exact cause of pre-eclampsia isn’t fully understood, but it’s believed to stem from abnormal placental development in early pregnancy. When the placenta doesn’t implant deeply enough into the uterine wall, it receives insufficient blood flow, triggering a cascade of chemical reactions that lead to the characteristic symptoms. Risk factors include first pregnancies, previous pre-eclampsia, multiple pregnancies, pre-existing medical conditions like diabetes or chronic hypertension, obesity, and maternal age over 40 or under 20.

Common symptoms of pre-eclampsia include persistent headaches that don’t respond to paracetamol, visual disturbances such as blurred vision or seeing flashing lights, severe pain just below the ribs (particularly on the right side), sudden swelling of the face, hands, or feet, and feeling generally unwell. Some women may also experience nausea or vomiting in late pregnancy, breathlessness, or a sudden increase in weight due to fluid retention. However, many women with pre-eclampsia have no obvious symptoms, which is why regular antenatal check-ups are essential.

It’s important to note that some symptoms of pre-eclampsia, such as mild swelling and headaches, can also be normal pregnancy symptoms. The key difference is the severity and persistence of these signs. If you experience severe headaches that won’t go away, sudden swelling, upper abdominal pain, or changes in vision, contact your midwife or maternity unit immediately, even if you’ve recently had a check-up. Early detection through routine blood pressure monitoring and urine tests at antenatal appointments can identify pre-eclampsia before symptoms become severe.

Certain factors significantly increase the risk of developing pre-eclampsia during pregnancy. High-risk factors include having had pre-eclampsia in a previous pregnancy (15-25% recurrence risk), chronic hypertension, diabetes (type 1 or 2), chronic kidney disease, or autoimmune conditions such as lupus or antiphospholipid syndrome. Women with multiple pregnancies (twins, triplets, or more) are also at elevated risk, as are first-time mothers, women over 40 years old, and those with a family history of pre-eclampsia. A BMI over 35 at the start of pregnancy is another significant risk factor.

According to NHS and NICE guidelines, women with one or more high-risk factors should be offered low-dose aspirin (150mg daily) from 12 weeks of pregnancy to reduce their risk of developing pre-eclampsia. Moderate risk factors include maternal age over 40 or a pregnancy interval of more than 10 years, BMI of 35 or more at first visit, and first pregnancy.

If you have two or more moderate risk factors, you may also be advised to take prophylactic aspirin. Discussing your individual risk profile with your midwife or obstetrician early in pregnancy allows for appropriate monitoring and preventive measures to be put in place.

Pre-eclampsia is diagnosed through a combination of blood pressure measurements and urine tests during routine antenatal appointments. A diagnosis is typically made when blood pressure readings are consistently 140/90 mmHg or higher after 20 weeks of pregnancy, accompanied by protein in the urine (proteinuria). Your midwife or doctor will also check for other signs such as swelling, review your symptoms, and may order additional blood tests to assess liver and kidney function, platelet count, and other markers of organ involvement.

Modern diagnostic approaches now include biomarker testing using PlGF (Placental Growth Factor) and sFlt-1 levels to help predict the likelihood of developing pre-eclampsia or assess disease severity.

The PlGF/sFlt-1 ratio provides valuable information about placental function and can help clinicians determine whether pre-eclampsia is likely to develop within the next few weeks, allowing for more targeted monitoring and management.

If pre-eclampsia is suspected or confirmed, you’ll be monitored more frequently with regular blood pressure checks, urine tests, blood tests, and ultrasound scans to assess your baby’s growth and wellbeing.

Pre-eclampsia can lead to serious complications for both mother and baby if left unmanaged. Maternal complications include eclampsia (seizures), which affects fewer than 3 in every 10,000 women giving birth in the UK; HELLP syndrome (a severe form affecting the liver and blood clotting system); stroke; kidney or liver failure; pulmonary oedema (fluid on the lungs); and placental abruption, where the placenta separates from the uterine wall. These complications can be life-threatening, and hypertensive disorders of pregnancy (which include pre-eclampsia) account for around 16% of maternal deaths globally.

For the baby, pre-eclampsia can cause intrauterine growth restriction (IUGR) due to reduced blood flow through the placenta, resulting in a smaller baby with potential long-term health implications.

The condition is also a leading cause of preterm birth, as early delivery may be necessary to protect the mother’s health, which can lead to complications associated with prematurity. In severe cases, pre-eclampsia can result in stillbirth.

However, with appropriate monitoring, early detection, and timely intervention, most women with pre-eclampsia deliver healthy babies, particularly when the condition is identified and managed properly by experienced healthcare professionals.

The only definitive cure for pre-eclampsia is delivery of the baby and placenta, but management depends on the severity of the condition and how far along you are in your pregnancy. For mild pre-eclampsia detected near term (after 37 weeks), your obstetrician may recommend induction of labour or planned delivery.

If diagnosed earlier in pregnancy, the focus shifts to careful monitoring to allow the baby more time to develop whilst keeping the mother safe.

This typically involves more frequent antenatal appointments, regular blood pressure monitoring, blood tests to check organ function, urine tests for protein levels, and ultrasound scans to monitor fetal growth and amniotic fluid levels.

Medication may be prescribed to manage symptoms and prevent complications. Antihypertensive medications help control high blood pressure, whilst magnesium sulphate (a medicine that helps prevent seizures) may be given to prevent eclamptic seizures if pre-eclampsia becomes severe.

In some cases, corticosteroids (steroids that help the baby’s lungs mature) are administered to help mature the baby’s lungs if early delivery is anticipated. Women with severe pre-eclampsia typically require hospital admission for close monitoring and may need emergency delivery regardless of gestational age to prevent life-threatening complications.

After delivery, blood pressure usually returns to normal within days to weeks, though some women require ongoing monitoring and medication during the postnatal period, as pre-eclampsia can occasionally develop or worsen after birth.

Whilst pre-eclampsia cannot be entirely prevented, evidence-based interventions can significantly reduce the risk in high-risk women. The most effective preventive measure is low-dose aspirin (150mg daily), which NICE recommends for women with high-risk factors, starting from 12 weeks of pregnancy until delivery. In the ASPRE trial (Rolnik et al.

, NEJM 2017), starting low-dose aspirin at 11-14 weeks reduced preterm pre-eclampsia by around 62% (1.6% versus 4.3%; odds ratio 0.38) in screen-positive high-risk women. Women should take aspirin at bedtime for optimal effectiveness, and it’s safe to use throughout pregnancy when prescribed for this purpose.

Beyond aspirin, maintaining a healthy lifestyle can support overall pregnancy health, though it won’t guarantee prevention of pre-eclampsia.

This includes attending all scheduled antenatal appointments for regular blood pressure and urine monitoring, maintaining a balanced diet rich in fruits and vegetables, staying physically active within recommended guidelines for pregnancy, and managing pre-existing conditions like diabetes or hypertension before and during pregnancy.

Early pregnancy screening and risk assessment allow healthcare providers to identify women who would benefit from increased monitoring and preventive treatment. If you’ve had pre-eclampsia in a previous pregnancy, speak with your GP or obstetrician before conceiving again to discuss personalised prevention strategies and optimal management for future pregnancies.