Influence of Maternal Aerobic Exercise During Pregnancy on Fetal Cardiac Function and Outflow

ABSTRACT Objectives To assess the effects of supervised prenatal aerobic exercise at recommended levels on fetal cardiac function and outflow in the 3rd trimester of pregnancy. We hypothesized that fetuses of aerobically-trained women compared to fetuses of non-exercising women would exhibit increased cardiac function and greater cardiac output. Study Design Secondary data analyses of a 20-week, randomized controlled exercise intervention trial in pregnant women between 2015 and 2018 in Eastern North Carolina were performed. Eligibility criteria included pregnant women cardiac function including fetal heart rate, right and left-ventricular stroke volume, stroke volume index, cardiac output, cardiac output index, and cardiac outflow including pulmonary and aortic valve diameters, peak flow velocity, and peak flow velocity-time integral (VTI). Fetal activity state (quiet vs active) during the echocardiogram and maternal aerobic capacity (VO2peak) served as covariates. Intention-to-treat and per protocol (participants attending ≥ 80% of exercise sessions) Analysis of Covariance regression models were performed. Results Of the 127 randomized participants, 66 and 50 participants were included in the intention-to-treat and per protocol analyses, respectively. Prenatal aerobic exercise significantly increased fetal right-ventricular cardiac measures of RV stroke volume (p=0.001) and stroke index via VTI (p=0.003), RV cardiac output (p=0.002) and cardiac index via VTI (p=0.006), as well as pulmonary artery diameter (p=0.02) and pulmonary valve VTI (p=0.03). Only in the ITT analysis was a significant differences in fetal LV cardiac outflow observed with greater aortic valve peak velocity (p=0.04) found among fetuses of aerobically-trained pregnant women. No other statistically significant between-group differences were found. Conclusions The findings of this study demonstrate that participation in prenatal aerobic exercise at recommended levels may improve fetal cardiac function and outflow parameters. Follow-up cardiovascular measures in the postnatal period are needed to determine potential long-term effects on the offspring’s cardiac function and outflow.