- To characterize the 24-h arterial pressure (AP) profile and the left ventricular (LV) structures and functions in women with pregnancy-associated hypertension. Twenty nulliparous pregnant women after 20 weeks' gestation, 10 normotensive and 10 hypertensive women matched for gestational age, were hemodynamically investigated using 24-h AP monitoring and Doppler echocardiography to determine LV structures and functions, both systolic and diastolic. The hypertensive women had significantly higher AP determinations throughout the 24 h, with no change in diurnal variation, i.e. nocturnal decline and early morning peaks. Their LV mass was greater and it was accompanied by a slight reduction in contractility and a significant reduction in LV relaxation. The increased AP was due to peripheral vasoconstriction, while cardiac output was preserved. It appears that pregnancy-associated hypertension is caused mainly by arterial vasoconstriction and not by higher cardiac output. The hypertension increases the LV mass, which is associated with a fall in LV relaxation.