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Abstract Introduction Pregnancy is a cardiovascular stress test, which is superimposed on already adverse trajectories for several health outcomes in individuals with obesity. As such, pregnancy is a critical period for cardiovascular disease (CVD) prevention, especially in people with obesity. Exercise training is a first-line therapy that reduces CVD risk by beneficial effects on cardiorespiratory fitness, cardiac function, and vascular outcomes such as endothelial-dependent dilatation. Purpose In a secondary analysis from the Exercise Training in Pregnancy (ETIP) study, we aimed to determine the effectiveness of exercise training during pregnancy on peak oxygen uptake (V̇O2peak), cardiac function, and flow-mediated dilatation of the brachial artery (FMD) throughout pregnancy and postpartum. We hypothesized that exercise training would improve these outcomes, in comparison with a no-exercise control group. Methods ETIP is a randomised controlled trial in which participants with a pre-pregnancy body mass index (BMI) ≥ 28 kg/m2 were randomly allocated to an exercise group or a control group in gestational week 12-18. Those in the exercise group were offered three weekly supervised exercise sessions comprising 35 minutes of moderate-intensity treadmill walking followed by 25 minutes of strength exercises. We measured V̇O2peak and FMD at baseline, in gestational week 34-37, and 3 months postpartum, and echocardiography in gestational week 14, 20, and 32, and 6-8 weeks postpartum. Differences between groups were determined using linear mixed models. Results Of the 91 participants included in ETIP, 87 participants (age: 31.3 ± 4.2 years, BMI: 34.6 ± 4.3 kg/m2) had data on V̇O2peak, cardiac function, and/or FMD from at least one time-point. There was no significant effect of exercise training on VO2peak in late pregnancy (gestational week 34-37), with an estimated effect of 1.7 mL/min/kg (95% confidence interval CI, -0.4 to 3.7), compared with the control group (p = .11), or postpartum (1.6 mL/min/kg, 95% CI, -0.2 to 3.4, p = .08). The participants had an average VO2peak of ~27 mL/kg/min 3 months postpartum, which is 14 mL/kg/min (34%) lower than average V̇O2peak of Norwegian females 20-39 years old. There were several significant effects of time (progressing pregnancy) on FMD and cardiac function parameters, but no significant between-group differences in either FMD or any of the echocardiographic outcomes. Only 50% of the participants in the exercise group fulfilled our pre-specified adherence criteria. Conclusion Offering pregnant individuals with BMI ≥ 28 kg/m2 a supervised exercise training intervention did not improve cardiorespiratory fitness, cardiac function parameters, or endothelial-dependent dilatation of the brachial artery. The main reason for no effect of the intervention on these outcomes was probably the low adherence to the exercise training.
Moholdt et al. (Sat,) studied this question.