Influence of antenatal physical exercise on haemodynamics in pregnant women: a flexible randomisation approach

Background: Normal pregnancy is associated with marked changes in haemodynamic function, however the influence and potential benefits of antenatal physical exercise at different stages of pregnancy and postpartum remain unclear. The aim of this study was therefore to characterise the influence of regular physical exercise on haemodynamic variables at different stages of pregnancy and also in the postpartum period. Methods: Fifity healthy pregnant women were recruited and randomly assigned (2 x 2 x 2 design) to a land or water-based exercise group or a control group. Exercising groups attended weekly classes from the 20th week of pregnancy onwards. Haemodynamic assessments (heart rate, cardiac output, stroke volume, total peripheral resistance, systolic and diastolic blood pressure and end diastolic index) were performed using the Task Force haemodynamic monitor at 12-16, 26-28, 34-36 and 12 weeks following birth, during a protocol including postural manoeurvres (supine and standing) and light exercise. Results: In response to an acute bout of exercise in the postpartum period, stroke volume and end diastolic index were greater in the exercise group than the non-exercising control group (p = 0.041 and p = 0.028 respectively). Total peripheral resistance and diastolic blood pressure were also lower (p = 0.015 and p = 0.007, respectively) in the exercise group. Diastolic blood pressure was lower in the exercise group during the second trimester (p = 0.030). Conclusions: Antenatal exercise does not appear to substantially alter maternal physiology with advancing gestation, speculating that the already vast changes in maternal physiology mask the influences of antenatal exercise, however it does appear to result in an improvement in a woman's haemodynamic function (enhanced ventricular ejection performance and reduced blood pressure) following the end of pregnancy.