Normal Blood Pressure in Pregnancy
by Donna Harvel Balo ARNP, CNM, MS

Q. I am curious to know what is considered "normal" blood pressure? Mine is all over the place, really low to the point I've fainted 3 times and now it's back up to normal. With my last pregnancy, there were times it was sky high (apparently) but with no ongoing signs of toxemia. How do they decide what's normal?

A. A "desirable" blood pressure is less than 120/80. For a pregnant woman, one of the most important things is what was average for the woman before pregnancy.

Hypertension of pregnancy is usually defined as 140/90 or greater, or a rise of 30mm of mercury in the systolic (top number) and/or a rise of 15mm of mercury in the diastolic (bottom number).

Low blood pressure can be a problem if it is causing someone to faint (syncope). The medical definition of hypotension is the systolic (top number) less than 90 with signs of dizziness and an increased pulse.