Associations of physical activity and sedentary time with aortic stiffness and autonomic function in early pregnancy

Rapid cardiovascular and autonomic adaptations occur during early pregnancy to accommodate augmented cardiac output and placental circulation, with inadequate adaptation associated with hypertensive pregnancy complications. Habitual physical activity (PA) and limiting time in sedentary behavior (SED) may improve pregnancy-related vascular and autonomic function. The objective of this study was to examine the magnitude of the predicted associations between device-measured PA and SED with cardiovascular and autonomic biomarkers including aortic stiffness, blood pressure variability (BPV), and baroreflex sensitivity (BRS) in the first trimester of pregnancy. Pregnant women (N = 92, 21-44 yr of age) free from cardiovascular disease were assessed between 10⁰ and 12⁶ weeks of gestation. Participants wore a thigh-mounted activPAL device for 7 days to assess PA (light intensity and moderate-to-vigorous intensity) and SED. Aortic stiffness was measured by noninvasive applanation tonometry and expressed as carotid-femoral pulse wave velocity (cfPWV). Beat-to-beat blood pressure (BP) and R-R intervals were synchronously recorded for 10 min via finger plethysmography and ECG to derive beat-to-beat BPV and spontaneous cardiovagal BRS (sequence method). In the entire group, neither PA nor SED was related to cfPWV, BPV, or BRS, and this finding was similar in nulliparous and parous pregnant women. In stratified analyses, the association between moderate-to-vigorous-intensity PA and cfPWV differed by gestational age (GA) such that this inverse association was only present in the 12th week of gestation (β = -0.365, P = 0.015). The present study indicates that PA and SED are not associated with aortic stiffness or autonomic function in the first trimester.NEW & NOTEWORTHY Pregnancy is characterized by profound maternal circulatory and autonomic adaptations, but the impact of modifiable factors, such as physical activity and sedentary behavior on vascular and autonomic function during pregnancy, is unclear. We demonstrate that device-measured physical activity and sedentary time are not associated with aortic stiffness, baroreflex sensitivity, and blood pressure variability during the first trimester. The beneficial effect of physical activity on aortic stiffness may become more pronounced with advancing gestational age.