Influence Of Maternal Exercise Types During Pregnancy On Fetal Cardiac Measures

PURPOSE: To assess the effects of different types of prenatal exercise on the fetal heart. We hypothesized that any type of pregnancy exercise, especially aerobic, would improve fetal cardiac function relative to fetuses of non-exercisers. METHODS: Participants were randomly assigned to 150 min/wk of either aerobic (AE), strength (SE), or combined (aerobic+strength; CE) moderate-intensity exercise, or non-exercise (control) group for ~24 weeks. At 36 weeks gestation, a blinded fetal echocardiogram was performed to assess fetal cardiac measures. Fetal activity state (FAS) was a covariate. Data were analyzed using ANOVA and regression. RESULTS: Data from 183 participants (60 AE, 33 SE, 40 CE, 50 control) were analyzed. Groups were similar, except for diastolic blood pressure (BP) and peak VO2; these were controlled in regression. For all fetal data, there are similar anatomical and functional measures. Stratifying by FAS, there are different aortic diameters, but similar functional measures in the active state, with no differences in the quiet state. For adherent participants, pooled and stratified by FAS, there were similar measures between groups. Right ventricular (RV) diastolic diameter was predicted (R2 = 0.47) by maternal age, systolic BP (SBP), and average exercise intensity. Exercise attendance predicted RV systolic diameter (R2 = 0.25). Furthermore, LV diastolic diameter (R2 = 0.22) and PV diameter (R2 = 0.68, p = .04).) were both predicted by fitness level, exercise type (CE) and intensity. While LV end-diastolic volume was predicted (R2 = 0.14, p = .04) by FAS and exercise type (CE). Similarly, PV flow velocity was predicted (R2 = 0.12, p = .01) by SBP and exercise type (CE = SE = AE). Fetal RV cardiac output (R2 = 0.58, p = .04) and cardiac index were both predicted by maternal HR, prepregnancy BMI, and exercise type (AE). Also, AV diameter was predicted (R2 = 0.12, p = .04) by fitness level and exercise type (AE). Fetal AV peak velocity (R2 = 0.35) and flow velocity (R2 = 0.32) were both predicted by SBP, exercise intensity and attendance (p < .05). CONCLUSIONS: These findings demonstrate that prenatal exercise (type, intensity, attendance) may improve fetal cardiac measures, especially CE or AE. Further research is needed to determine if these differences persist after birth.