Autonomic nervous dysfunction in severe pre-eclampsia.

We evaluated autonomic nervous function in 14 subjects with severe pre-eclampsia and 11 subjects with normal third-trimester pregnancies using standard cardiovascular tests, i.e. heart rate responses to deep breathing and standing up, and blood pressure response to standing up. Both of the heart rate responses were lower in subjects with severe pre-eclampsia than in the control group (P less than 0.01 and P less than 0.001, respectively). Four subjects with severe pre-eclampsia had postural hypotension, defined as a systolic blood pressure fall of at least 30 mmHg on standing. Our results show that severe pre-eclampsia may be associated with autonomic nervous dysfunction. The inability to regulate heart rate and blood pressure in response to postural alterations may compromise the placental and renal blood flow in certain conditions, emphasising the importance of bed rest in severe pre-eclampsia.