Question

I have heard that pregnancy can cause high blood pressure. How common is this and how dangerous is it? Does the high blood pressure go away after you have the baby?

Answer

Some women do develop high blood pressure during pregnancy. This is known as Pregnancy Induced Hypertension (PIH) and is closely related to preeclampsia and toxemia. It can be dangerous. Preeclampsia is a disorder that occurs only during pregnancy and the postpartum period. It’s characterized by high blood pressure and elevated protein in the urine (as a result of kidney problems). Preeclampsia typically begins after the 20^th week of pregnancy.

Preeclampsia can harm the placenta as well as the mother’s kidneys, liver and brain. It can also cause fetal complications such as low birth weight, premature birth and stillbirth. When preeclampsia produces symptoms, they can include swelling, sudden weight gain, headaches and changes in vision. Not all women have symptoms, however.

According to the National Heart, Lung, and Blood Institute (NHLBI), high blood pressure problems affect 6–8 percent of all pregnancies in the United States, with nearly 70 percent of these in first-time pregnancies. The rate of preeclampsia has increased over the past decade by nearly one-third. This is due in part to a rise in numbers of older mothers and multiple births, where preeclampsia is more likely to develop.

You are at a higher risk for developing preeclampsia if you:

• Have high blood pressure before becoming pregnant
• Have developed high blood pressure or preeclampsia in a previous pregnancy
• Are obese prior to pregnancy
• Are under age 20 or over age 40
• Are pregnant with more than one baby
• Have diabetes, kidney disease, rheumatoid arthritis, lupus or scleroderma

There is no proven way to prevent pregnancy induced hypertension or preeclampsia and no test that will predict or diagnose these conditions. Only regular visits to your doctor will ensure that you’re having a safe pregnancy. Your doctor will track your blood pressure and check the level of protein in your urine. Follow all of your doctor’s recommendations and do what you can to help control your blood pressure. Limit your sodium intake and get regular physical activity.

In women who develop preeclampsia after the 20^th week of their first pregnancy, the increased blood pressure and other short-term complications typically go away about six weeks after delivery. The long-term effects of these conditions may vary but in general do not increase a woman’s chance for developing chronic high blood pressure or other cardiovascular problems.

This content is reviewed regularly. Last updated 11/11/09.