| Summary |
The extent of the health benefits of exercise during pregnancy is just beginning to be explored and developed. The purpose of this study was to compare the effects of aerobic and circuit training throughout pregnancy on maternal, fetal, and neonatal health outcomes. We hypothesized that we would find: (1) managed gestational weight gain (GWG), decreased body fat gain, and decreased maternal resting heart rate (RHR) in women throughout pregnancy as follows: aerobic training group = circuit training group > control group; (2) increased stroke volume (SV), ejection fraction (EF), and cardiac output (CO) at 34 weeks in fetuses exposed to maternal exercise training with greatest differences in the aerobic training group = circuit training group > control group; and (3) no differences in fetal anatomical cardiovascular measurements, fetal anthropometric measurements, or neonatal measurements of both exercising groups compared to controls. Participants completed three 45 minute sessions weekly from 16 weeks gestational age (GA) to 36 weeks GA of aerobic or circuit training, with controls completing monthly measurements and breathing exercises. We measured maternal RHR and blood pressure (BP) at each exercise session, maternal body composition monthly, 34 week fetal anthropometric and heart measures, and obtained neonatal measures at birth. Statistical analyses included t-tests, ANOVAs, and MANOVAs. Participants (n=15) were similar in age, parity, and pre-pregnancy body mass index (BMI), with a diversity of pre-pregnancy activity levels. All groups had similar GWG and change in BMI throughout gestation. The aerobic training (AT) group gained significantly less body fat % throughout gestation relative to the circuit training (CT) (p=0.04) and control (p=0.03) groups. No differences were found between groups for change in RHR or diastolic BP (DBP). Exercising women experienced less of an increase in resting SBP relative to controls (p=0.01). Pre-training serum lipid levels were similar between groups. At the post-training measurement, the CT group had higher levels of total cholesterol and high density lipoprotein (HDL) cholesterol relative to the AT and control groups. The CT group had trends of a greater change in TC and low density lipoprotein (LDL) cholesterol throughout gestation relative to the AT and control groups. No differences were found between groups for fetal anthropometric measures, anatomical heart measures, or left ventricular (LV) physiological heart measures of SV, EF, and CO at 34 weeks GA. Fetuses exposed to CT had significantly increased right ventricular (RV) SV (p=0.03), with a trend towards increased RV EF relative to control fetuses (p=0.06). No differences were found in fetal RV CO between groups. However, there were trends for fetuses exposed to maternal exercise training to have greater CO relative to control fetuses. No differences were found between groups for neonatal birth weight, birth length, 1 min APGAR scores, and 5 min APGAR scores. Neonates exposed to CT had significantly increased (p=0.03) Ponderal Index (PI) compared to controls. Based on recommended exercise guidelines by the American Congress of Obstetrics and Gynecology (ACOG), these results suggest that 1) AT during pregnancy decreases body fat gain and improves maternal heart health, 2) CT during pregnancy improves fetal heart function and development, and 3) different types of exercise do not adversely affect growth and may impact neonatal body composition. Therefore, in order to maximize maternal and fetal benefits, it seems best to perform both aerobic and strength training during pregnancy. |
