I had high blood pressure with my second near the end of my pregnancy. I had to take medication, which didn't really help it get better, but it didn't get any worse. Ended up being induced because of my blood pressure. I've never had an issue with my BP, even in my first pregnancy, so I'm pretty convinced that I had a problem the second time around because I gained so much weight (70-80lbs).
High blood pressure during pregnancy may lead to three different types of conditions. These are chronic hypertension, Gestational hypertension and chronic hypertension with superimposed preeclampsia. It causes abnormal swelling in hands and face, seeing spots or having changes in vision, nausea or vomiting later in pregnancy, persistent headaches, upper abdominal pain and difficulty in breathing. Along with these symptoms if the blood pressure increases too much then it may become fatal to both the mother as well as the baby. So be on a regular visit for a medical check-up and do as per the advice of the doctor.