Many medical experts say that there is nothing pregnant women can do to prevent preeclampsia. But there are some studies that suggest that adequate amounts of vitamins, especially C, E, A and D can prevent the condition from developing. One thing that no pregnancy and birth professional, whether a midwife or an OB/GYN, would argue with is that taking good care of your health during your ensure pregnancy, and making sure you receive the recommended dosages of vitamins, is good for both you and your unborn baby. (See Best foods for the first trimester, for example!) It might prevent preeclampsia, or it might not, but eating healthily and being active is definitely the responsible thing to do!
As for treatment of preeclampsia, there is none. The only thing that makes preeclampsia go away is giving birth. If you do a little bit of reading on the subject, you'll have this fact waved in your face many times over. Does that mean that you need an immediate induction or cesarean section if you develop either high blood pressure or have protein in your urine during your third trimester? Not necessarily, but you will certainly need to be closely monitored, and may require a hospital stay. If your blood pressure reaches dangerously high levels, your doctor could step in immediately.