Reversed diurnal blood pressure rhythm in hypertensive pregnancies.

1. Reversal of the normal diurnal blood pressure pattern has been demonstrated in women with severe hypertension and renal impairment in pregnancy (pre-eclampsia). 2. Maximum arterial pressure occurred at night in these women. The phenomenon was not due to hypotensive drug therapy or posture. Patients with uncomplicated essential hypertension in pregnancy retained a normal diurnal blood pressure pattern. 3. Nocturnal hypertension in pre-eclampsia is of theoretical interest and practical importance.