It usually occurs in the second half of pregnancy and can be mild or severe. During pregnancy, your blood volume increases. Normally the blood vessels in your body relax during this time to help accommodate the increased blood flow. When pre-eclampsia occurs, the blood vessels don't relax and blood pressure rises. Pre-eclampsia occurs in about 1 out of 10 pregnancies.
Some women are at higher risk.
The pregnant woman with pre-eclampsia can experience damage to her kidneys and liver. This damage usually repairs itself after the baby is delivered. Sometimes fluid can accumulate in the lungs of a pregnant woman with this disease. If pre-eclampsia is severe, blood clotting can be affected and there is a risk of internal bleeding. It is a complication that occurs in a small group of women with pre-eclampsia or pregnancy complicated by hypertension.