Pregnant friends! Please take your blood pressure every day while pregnant. That is my main piece of advice. Here are the symptoms of preeclampsia/HELLP - but beware that it can come on *very* quickly and be very serious, very fast.
High blood pressure (pregnant women - get an at home blood pressure cuff from your local drugstore and take it every day! Ask your doctor what your regular blood pressure should be)
High blood pressure, along with one of these other symptoms:
Swelling! In face, hands, feet
Sudden weight gain (approx. more than 5 pounds in one week)
Upper right quadrant paid
Protein in your urine (this will need to be tested at doctor)