Chronic hypertension in pregnancy.

Pregnancies in women with chronic hypertension are at increased risk of superimposed pre-eclampsia, abruptio placentae, fetal growth retardation and prematurity. The frequencies of these complications are increased in those women who have high-risk chronic hypertension, ie severe hypertension or pre-existing cardiovascular or renal diseases, as well as in those with target organ damage. Such women should receive antihypertensive therapy and close management to improve maternal and fetal outcome. In women with low-risk chronic hypertension, antihypertensive treatments do not improve pregnancy outcome. Prophylactic low-dose acetylsalicylic acid treatment does not reduce the frequency of superimposed pre-eclampsia nor does it improve perinatal outcome in these pregnancies.