Objectives: Epidemiological studies show that women with pregnancies complicated by hypertension have an increased risk of cardiovascular morbidity later in life. The underlying mechanisms to the risk increase remain largely unknown. This study evaluated sympathetic nerve activity in women with hypertensive pregnancies 40 years earlier compared to women with normotensive pregnancies. We hypothesized that sympathetic outflow would be increased in women with previous hypertensive pregnancies and that this partly may explain the increased cardiovascular risk.
Methods: Sympathetic nerve activity to the muscle vascular bed [muscle sympathetic nerve activity (MSNA)] was recorded in 28 women, 18 with and 10 without a hypertensive manifestation during pregnancy. Women were also examined with ambulatory blood pressure measurements, pulse wave velocity, blood pressure response during Stroop test and laboratory analysis.
Results: Women with previous hypertensive pregnancies did not show an increased sympathetic outflow compared to women with normotensive pregnancies. In eight women with treated hypertension sympathetic outflow was increased compared to normotensive women despite similar ambulatory blood pressure values (P < 0.05). During Stroop test the hypertensive women showed increased systolic blood pressure and also displayed the highest augmentation index compared to normotensive women (P < 0.05).
Conclusion: Hypertensive pregnancies per se were not associated with increased sympathetic outflow 40 years later. The increased cardiovascular risk in women with previous hypertensive pregnancies cannot be explained by chronic activation of the sympathetic nervous system.In women with previous hypertensive pregnancies, still hypertensive though well controlled, sympathetic outflow and arterial stiffness were, however, increased compared to normotensive counterparts.