Effects of High Blood Pressure in Pregnancy

Although many women with high blood pressure in pregnancy have healthy babies without serious problems, high blood pressure can be dangerous for both the mother and the fetus. These effects range from mild to severe.

 

Women with pre-existing or chronic high blood pressure are more likely to have certain complications during pregnancy than those with normal blood pressure. High blood pressure can harm the mother's kidneys and other organs, and it can cause low birth weight and early delivery. In the most serious cases, the mother develops preeclampsia (also known as pregnancy-induced hypertension, toxemia of pregnancy, or acute hypertensive disease of pregnancy), which can threaten the lives of both the mother and the fetus.

 

How Common Is High Blood Pressure in Pregnancy?

High blood pressure in pregnancy occurs in 6 to 8 percent of all pregnancies in the United States, about 70 percent of which are first-time pregnancies.

 

Although the proportion of pregnancies with gestational hypertension and eclampsia has remained about the same in the United States over the past decade, the rate of preeclampsia has increased by nearly one-third. This increase is due, in part, to a rise in the numbers of older mothers and of multiple births, where preeclampsia occurs more frequently. For example, in 1998, birth rates among women ages 30 to 44 and the number of births to women ages 45 and older were at the highest levels in three decades, according to the National Center for Health Statistics. With the advent of in vitro fertilization (IVF), between 1980 and 1998, rates of twin births increased about 50 percent overall and 1,000 percent among women ages 45 to 49; rates of triplet and other higher-order multiple births jumped more than 400 percent overall and 1,000 percent among women in their 40s.