Cardiovascular autonomic responses to head-up tilt in gestational hypertension and normal pregnancy

The aim of the present study was to evaluate the influence of gestational hypertension on hemodynamics and cardiovascular autonomic regulation at rest and their responses to head-up tilt (HUT). We prospectively studied 56 pregnant women (28 with gestational hypertension and 28 healthy pregnant women) during the third trimester of pregnancy and 3 months after pregnancy.

In women with pregnancy-induced hypertension, compared with control women, there were significant differences in hemodynamics and in markers of cardiovascular regulation (p < 0.05 to p < 0.001). Postural change from the supine to the upright position was associated with significant changes in hemodynamic responses in both groups during pregnancy (from p < 0.05 to p < 0.001). Regulatory response to HUT in both groups was characterized with a decrease in HF power and increase in LF/HF ratio (from p < 0.01 to p < 0.001). Responses to HUT in total power and VLF power were attenuated in hypertensive pregnancies (p < 0.001 to p < 0.01, respectively, vs control group).

Our results suggest that autonomic cardiovascular regulation may not play a major role in women with gestational hypertension . The lack of irreversible changes in autonomic nervous function in hypertensive women appeared to be a feature of gestational-induced hypertension.