Pre-eclampsia (PE) happens in pregnancy. It features new onset high blood pressure. It is a major cause of problems to the mother and unborn child. It can lead to health problems in mother and child in the future, which causes a public health problem. We do not know everything about it, but we think it starts in the placenta (the organ that nourishes the unborn child). At this time, we do not know who will get PE. We want to study the placenta, to learn more about the disease.