AUTONOMIC HEMODYNAMIC CONTROL IN PREGNANCY-INDUCED HYPERTENSION

Objective: To elucidate the role of the parasympathetic and sympatheti c control of circulation in pregnancy-induced hypertension (PIH) and t o investigate whether the short-term regulation of blood pressure is d isturbed in PM. Methods: The Valsalva maneuver, the deep breathing tes t, the active orthostatic test, and the isometric handgrip test were u sed to study the autonomic circulatory control in 14 patients with PIH and 14 healthy pregnant controls. The Finapres(R) method was used to assess blood pressure continuously and noninvasively during the tests. Main Outcome Measures: The heart rate and blood pressure responses to standard cardiovascular reflex tests. Results: The Valsalva maneuver reduced the systolic blood pressure significantly more in PIH than in healthy pregnant controls (-19% vs. -10%, P = 0.02). In the orthostati c test the rise in diastolic blood pressure (20% vs. 29%, P = 0.03) an d in the heart rate (19 bpm vs. 24 bpm, P = 0.05), and the max/min rat io (1.31 vs. 1.48, P = 0.04) were smaller in the PIH group. Conclusion : The changes in blood pressure and heart rate responses indicate that the autonomic control of hemodynamics is disturbed in PIH. The regula tion of the sympathetically mediated peripheral vasoconstriction is im paired and the baroreflex sensitivity may be decreased.