It depends on what your "normal" blood pressure is. What is high for one person may not be for someone else. Most people suggest 120/80 as a guideline. Its the second number that is the most important one to watch. If that starts to drift over ninety it starts to be a concern. It is not unusual for blood pressure to raise a little in pregnancy. But if it continues to rise you may need medication to stabilise it.
However if you start to get any other symptoms, especially swelling in the face or hands, protein in the urine, fuzzy vision or basically anything strange, go straight back to your midwife/doctor as these can be signs of pre-eclampsia and you will need to be monitered. A blood test can check for this if necessary. The midwife is probably doing urine tests with the sticks each time you see her to check the protein levels.
This happened to me in the last month of pregnancy, my bp shot up and I began to get rising levels of protein in my urine. I strangely felt otherwise fine and I had no swelling but they induced me a week early just to be on the safe side.
If you have any questions just ask and I will do my best to answer them, its a subject I became quite well aquainted with.
Take care of yourself and your precious bundle
Leanne, NZ, Ella age 2 & Sam age 6months