Pre-eclampsia cannot happen until at least the 20th week of pregnancy. Most cases occur in the third trimester (from week 27 to the birth of the baby).
Early symptoms
Pregnant women with pre-eclampsia develop the following symptoms first:
You probably won't notice these symptoms, but your GP or midwife should pick them up during your antenatal appointments.
High blood pressure affects 10-15% of all pregnant women, so this alone does not suggest pre-eclampsia. However, the presence of protein in the urine is a good indicator of the condition.
Progressive symptoms
As pre-eclampsia develops, it can cause fluid retention (oedema), which often causes sudden swelling of the feet, ankles, face and hands.
Oedema is another common symptom of pregnancy, but it tends to be in the lower parts of the body, such as the feet and ankles. It will gradually build up during the day. If the swelling is sudden, and it particularly affects the face and hands, it could be pre-eclampsia.
As pre-eclampsia progresses, it may cause:
- severe headaches
- vision problems, such as blurring or seeing flashing lights
- pain in the upper abdomen (just below the ribs)
- vomiting
- excessive weight gain due to fluid retention
- feeling generally unwell
If you notice any symptoms of pre-eclampsia, seek medical advice immediately by calling your GP surgery or NHS Direct on 0845 4647.
Without immediate treatment, pre-eclampsia may lead to a number of serious complications, including:
- eclampsia (convulsions)
- HELLP syndrome - a combined liver and blood clotting disorder
- stroke
However, these complications are rare.
Read more about the complications of pre-eclampsia.
Symptoms in the unborn baby
The main sign of pre-eclampsia in the unborn baby is slow growth. This is caused by poor blood supply through the placenta to the baby.
The growing baby receives less oxygen and fewer nutrients than it should, which can affect development. This is called intra-uterine growth restriction, or intra-uterine growth retardation.
