It's normal for blood pressure to go up and down throughout the day. But if it stays up, you have high blood pressure. Another name for high blood pressure is hypertension.

Blood pressure is closely watched during pregnancy. High blood pressure can limit the baby's growth or cause other serious problems.

Some people have high blood pressure before they get pregnant (chronic high blood pressure). Others may develop high blood pressure that starts in the second or third trimester (gestational hypertension). Sometimes high blood pressure is a first sign of preeclampsia. This condition can be dangerous for both you and your baby.