Pre-eclampsia explained: warning signs and urgent care

A serious pregnancy emergency

Pre-eclampsia is not a minor part of pregnancy — it is a condition that must be taken seriously. It usually appears after 20 weeks of pregnancy and can develop, or first show itself, in the days after birth. The key warning signs are a severe headache, problems with vision such as blurring or flashing lights, sudden or severe swelling of the face, hands or feet, pain just below the ribs, feeling suddenly unwell, or vomiting. If you are pregnant, or have recently given birth, and have these symptoms, you need urgent maternity assessment straight away. Do not wait to see if they pass — contact your maternity unit or, if very unwell, seek emergency help.

What is happening in the body

Pre-eclampsia is thought to start with a problem in the placenta, the organ that supplies the baby. This leads to raised blood pressure and to protein leaking into the urine, a sign that the kidneys are affected. As it progresses, it can strain the liver, the blood-clotting system and the brain, and it reduces the blood flow to the baby, which can slow the baby's growth. In its most severe forms it can lead to seizures (a condition called eclampsia) or serious organ complications. Because these changes can build up silently before symptoms appear, blood pressure and urine are checked at every routine antenatal appointment to catch them early.

Who is more at risk

Pre-eclampsia is more likely in some pregnancies than others. Higher-risk situations include a first pregnancy, a previous pregnancy with pre-eclampsia, a gap of ten years or more since the last pregnancy, being over 40, expecting twins or more, a raised body weight, and existing conditions such as high blood pressure, kidney disease, diabetes or certain autoimmune conditions. A family history of pre-eclampsia also raises the chance. Because of this, women at higher risk are often advised to take a low-dose preventive medicine during pregnancy on their clinician's advice, and are watched more closely. Having risk factors does not mean pre-eclampsia will happen, but it does mean extra vigilance is sensible.

How it is found and monitored

Much of the time, pre-eclampsia is picked up not by symptoms but by routine checks. At antenatal appointments, blood pressure is measured and urine is tested for protein — a rise in both is a key clue. If pre-eclampsia is suspected, blood tests check how the kidneys, liver and clotting are working, and scans assess the baby's growth and the blood flow to the placenta. Depending on severity, a woman may be monitored closely as an outpatient or admitted to hospital. This is why attending every antenatal appointment matters, and why any new symptoms between appointments should be reported at once rather than waited on.

Treatment and the outlook

The only complete cure for pre-eclampsia is the birth of the baby and delivery of the placenta, so treatment aims to keep mother and baby safe until birth can be arranged at the safest time. Blood pressure is controlled with medicines that are safe in pregnancy, and close monitoring watches for any worsening. If the condition becomes severe, or the pregnancy is far enough along, the baby may need to be born earlier than planned, sometimes by induced labour or caesarean. Careful care continues after birth, as pre-eclampsia can appear or worsen in the days afterwards. With prompt recognition and good maternity care, most women recover fully, and blood pressure usually returns to normal.