What are the types of high blood pressure during pregnancy?

Sometimes high blood pressure is present before pregnancy. In other cases, high blood pressure develops during pregnancy.

• Gestational hypertension. Women with gestational hypertension have high blood pressure that develops after 20 weeks of pregnancy. There is no excess protein in the urine or other signs of organ damage. Some women with gestational hypertension eventually develop preeclampsia.
• Chronic hypertension. Chronic hypertension is high blood pressure that was present before pregnancy or that occurs before 20 weeks of pregnancy. But because high blood pressure usually doesn't have symptoms, it might be hard to determine when it began.
• Chronic hypertension with superimposed preeclampsia. This condition occurs in women with chronic hypertension before pregnancy who develop worsening high blood pressure and protein in the urine or other blood pressure related complications during pregnancy.

• Preeclampsia. Preeclampsia occurs when hypertension develops after 20 weeks of pregnancy, and is associated with signs of damage to other organ systems, including the kidneys, liver, blood or brain. Untreated preeclampsia can lead to serious — even fatal — complications for mother and baby, including development of seizures (eclampsia).

  Previously, preeclampsia was diagnosed only if a pregnant woman had high blood pressure and protein in her urine. Experts now know that it's possible to have preeclampsia without having protein in the urine.