Pre-eclampsia

What is pre-eclampsia?

Pre-eclampsia is a disorder which typically occurs after 20 weeks of pregnancy. Signs of pre-eclampsia are usually high blood pressure combined with the presence of protein in the urine. However, in the absence of protein in the urine, other symptoms may be present alongside high blood pressure. These include headaches, blurred or altered vision, upper abdominal pain, oedema (swelling of the face, wrists or ankles) or abnormal blood test results. If left untreated pre-eclampsia can escalate to the more dangerous condition, eclampsia. This results in fitting and in severe cases, death, in the mother and sometimes the baby.

What causes pre-eclampsia?

Although pre-eclampsia has been recognised as a disorder for around 150 years, its exact cause remains unknown. We know that 10-15% of women pregnant for the first time will develop pre-eclampsia. We also know that women are more likely to get pre-eclampsia if they have a close family relative with a history of pre-eclampsia. Also, women who have had one pregnancy marked by the disorder then have an increased chance (10-25%) of developing it in a subsequent pregnancy. However, women with a previous normal pregnancy or pregnancies (no pre-eclampsia) have less chance of developing it in subsequent pregnancies.

What are the implications?

If a woman shows symptoms of pre-eclampsia at any stage during her pregnancy, she will be monitored carefully. Sometimes, a woman will have to be admitted to hospital so that her symptoms, especially blood pressure, can be managed closely. The presence of pre-eclampsia may mean labour needs to be induced early to stop it escalating to eclampsia. At least 15% of all pre-term births are a result of this. Babies born to mothers with pre-eclampsia may also be small for gestational age because their growth may have been affected by the disorder. It is estimated that around 1,000 babies in the UK die each year from the effects of pre-eclampsia. In the most serious cases of pre-eclampsia, where the disease does escalate to the condition eclampsia, a woman might suffer fits, liver and kidney failure, difficulty breathing, and/or problems with blood clotting. Seven women in the UK die each year from the effects of pre-eclampsia, and worldwide it is responsible for the death of over 200,000 women each year.

What can be done to treat pre-eclampsia?

Doctors can give drugs to alleviate some of the symptoms, but the only cure for pre-eclampsia is to deliver the baby and the placenta. It is therefore the cause of around 15% of premature births.

Higher risk factors

The risk of developing pre-eclampsia is higher in women carrying multiple pregnancies (twins or triplets). And while women with previous normal pregnancies have less chance of developing pre-eclampsia in subsequent pregnancies, mothers who start another family with a new partner, have the same risk as women pregnant for the first time. It is also accepted that women over 35 are at a higher risk.