COMPARING THE INFLUENCE OF EXERCISE DURING PREGNANCY ON SIBLING HEART OUTCOMES

Abstract

There is an increase in the development of cardiovascular disease (CVD) risk factors in adults and children. Exercise is known to decrease CVD risk factors. Similarly, exercise during pregnancy improves maternal and fetal/infant heart health. Although research suggests exercise influences infant heart function, others believe this is due to inherent differences or characteristics of the mother; however, little research has been done to control for maternal background. One way to assess if an infant is born with a healthier heart is to compare siblings exposed or not exposed to exercise, thus controlling for maternal/genetic differences. Thus, determining whether exercise during pregnancy positively influences heart outcomes could program the next generation for a healthier life before birth. Objective: Therefore, the purpose of this study is to determine the effects of exercise during pregnancy on sibling heart outcomes. I hypothesize that siblings exposed to exercise in utero will have improved heart outcomes compared to siblings not exposed to exercise in utero. Methods: Data was collected from women with low-risk, singleton pregnancies who received clearance from their physician that they could participate in physical activity, had a previous sedentary or active lifestyle; were between the ages 18 and 40; had a body mass index (BMI) of 18.5-39.9 before pregnancy and were between 13 to 16 weeks pregnant. Participants performed a treadmill test and 1-repitition maximum tests, and were randomized via computer sequencing (GraphPad, Boston, USA) to exercise (aerobic (AE), resistance (RE), combination (aerobic + resistance; AERE) or a stretching/breathing control group (CON). Throughout the study, participants exercised for 150 minutes/week from enrollment until delivery (~40 wks). One-month infant heart measures were analyzed to compare sibling heart outcomes. For this analysis, we examined the influence exercise, any type, or no exercise on sibling heart outcomes by comparing heart rate (HR), and cardiac time intervals from EKG recordings. Sibling heart outcomes were compared with t-tests (exercise vs. control) and ANOVA (4 group comparison). Regressions were performed to assess predictors of sibling heart outcomes. All analyses were completed using IBM SPSS Software Version 29 (Chicago, Illinois) or the SAS JMP Pro Software Version 17 (Cary, NC). Results: The study focused on 13 women who participated twice, once as a control and once in an exercise group. Maternal characteristics such as age, weight, and BMI showed no significant differences between the two groups. Similarly, infant descriptors like gender, birth weight, and APGAR scores were comparable between groups. No significant differences were found in sibling heart outcomes, although QRS complex length showed a trend towards variation based on exercise type. Regression analysis indicated that maternal exercise group and pre-pregnancy BMI predicted one-month infant QRS length, while maternal exercise attendance predicted corrected QT interval. Overall, the study found no significant differences between the control and exercise groups. Discussion: This analysis aimed to compare one-month infant heart outcomes between siblings exposed to exercise in utero and those not exposed. Contrary to the hypothesis, the study found no significant differences in heart outcomes on EKG between the two groups. However, trends indicated increased QRS duration, suggesting greater left ventricular muscle mass in infants exposed to exercise. This was particularly evident in the aerobic exercise group. The study highlighted that EKGs might not be sensitive enough to detect subtle differences in healthy populations. Despite the small sample size, the findings suggest that maternal exercise could positively impact infant heart health, particularly in terms of left ventricular development. Further research with larger sample sizes and more sensitive measures is needed to confirm these results and understand the mechanisms behind these potential benefits.