What causes Pre Eclampsia?

The precise cause of Pre Eclampsia is unknown. However, genetic factors are probably involved, given women whose mothers and/or sisters have suffered Pre Eclampsia are at increased risk of the disease themselves.

There is good evidence that the placenta is centrally involved in the development of Pre Eclampsia. The placenta is a specialised organ which forms in the uterus during pregnancy. It receives blood from the mother and transfers oxygen and nutrition from the mother across to the baby's circulation, thereby helping the baby to grow and develop.

It seems that in Pre Eclampsia, the placenta does not receive sufficient maternal blood for its requirements, which apparently results in a malfunction within the placental tissue. This malfunction produces factors which pass from the placenta back into the mother's circulation. These factors damage the mother's blood vessels, the result of which is increasing blood pressure. As well, kidney function is disturbed and blood proteins leak from the mother's circulation through the kidney into the urine. As Pre Eclampsia worsens, other organs are affected, including the mother's liver, lungs, brain, heart and blood clotting system. Dangerous complications such as eclampsia (convulsions), cerebral haemorrhage (stroke), pulmonary oedema (fluid in the lungs from heart failure), kidney failure, liver damage and thinning of the blood (disseminated intravascularcoagulation) can occur in serious cases. However, these complications are fortunately rare.

Medical information supplied by:
Professor Shaun Brennecke
Director of Perinatal Medicine and University of Melbourne Department Head of Obstetrics and Gynaecology at the Royal Women's Hospital, Melbourne