Autonomic control and antioxidant status during early pregnancy in formerly preeclamptic women

Abstract

In formerly pre‐eclamptic women plasma volume is lower (LPV group) than in women who had a normal pregnancy and normal plasma volume (NPV). Blood pressure variability (BPV), heart rate variability (HRV) and baroreflex sensitivity (BRS) were compared in women with LPV (47.7 ml/kg lean body mass, n=7) and NPV (57.2 ml/kg lbm, n=7) before and during a new pregnancy at 8, 12, 16 and 20 weeks during pregnancy. The anti‐oxidant status was assessed if changes in oxidative stress were related to those in BRS. Systolic BP was slightly (about 5 mmHg) lower in LPV than in NPV before and during pregnancy. Before pregnancy low frequency LF‐BPV and LF‐HRV were slightly greater in LPV than in NPV. However, during pregnancy, both LF‐BPV and LF‐HRV were slightly lower in LPV than NPV. BRS increased during pregnancy by 20% in NPV and by 40% in LPV, but between group differences were not statistically significant. Overall these data indicate that autonomic adaptations to pregnancy and changes in BPV, HRV and BRS were comparable in women with LPV and NPV. Remarkably, plasma anti‐oxidant levels fell during pregnancy in NPV from 484 to 384 μM Trolox equivalents and in LPV and from 487 to 413 μM Trolox equivalents. These data indicate that oxidative stress increases during early pregnancy and therefore are in contrast with previous suggestions that increased oxidative stress decreases BRS.