Echocardiographic haemodynamic and left ventricular parameters were determined in twenty-one normontensives and thirty-six hypertensives during the last trimester of pregnancy. 2. Equivalent blood pressure control was obtained in hypertensives with bet rest only, oxprenolol or methyldopa, but remained above normotensive levels. 3. Cardiac output was elevated in the last trimester of pregnancy in normotensivves and hypertensives. 4. Left ventricular mass was increased in normal pregnancy, but displayed an exaggerated increase in hypertensives. 5. Total peripheral resistance was inappropriately elevated in hypertensive pregnancy, but was normalized in the oxprenolol-treated group. 6. There was no reduction in heart rate or cardiac output in the beta-adrenoreceptor blocker-treated group. This feature, in combination with lowered peripheral resistance, may contribute to the improvement in foetal outcome observed in maternal hypertension of pregnancy treated with oxprenolol.
