The Effects of Prenatal Exercise on Infant Gross Motor Skills and Insulin-Like Growth Factor I & II

Abstract

ABSTRACT Prenatal exercise has been shown to improve both maternal and infant health outcomes. Previous research conducted in our lab has shown that there is a positive relationship between aerobic exercise and infant gross motor skills at one month of age. However, it remains unknown the effects of prenatal exercise on various frequency, intensity, time, type, and volume (FITT-V ) metrics at one month of age, the duration of these gross motor skill improvements, as well as the mechanism behind these improvements. The purpose of this dissertation was to address these gaps in the literature through the following aims: aim 1a: To determine the effects of prenatal exercise modes and exercise metrics (FITT-V) on 1-month infant gross motor skills, aim 1b: To determine the effects of prenatal exercise mode on gross motor skill trajectories at 1, 6, and 12 month, aim 2: Evaluate the correlation of prenatal exercise with umbilical cord plasma IGF concentrations as well as the correlation between IGF concentrations with infant gross motor skills. Peabody Developmental Motor Scales 2nd Edition (PDMS-2) scores and cord plasma were obtained from infants of healthy pregnant women who participated in our randomized control trial intervention. Women participated in the study from <16-wks gestation until delivery and those in the exercise groups completed 150 min of moderate intensity aerobic (AE), resistance (RE), or combination (CE) exercise per week. For all aims, offspring completed an infant gross motor skill assessment, the Peabody Developmental Motor Scales 2nd Edition (PDMS-2). This assessment was completed by a pediatric physical therapist with 40 years experience who was blinded to group randomization. For aim 2, umbilical cord plasma was analyzed for insulin-like growth factors I & II (IGF I &II) using MULTIPLEX MAP kits and Luminex xMAP technology to quantify biomarker concentration. For aim 1a, PDMS-2 scores were higher in infants born to women exercising at a higher intensity during pregnancy. When examining differences in gender, we found a trend towards higher PDMS-2 Reflex scores in females and higher Stationary and Locomotion scores in the males. Aim 1b, we found that all prenatal exercise modes elicited enhanced gross motor skills when compared to the attention control (CON) group. Moreover, we found that prenatal exercise, specifically CE, positively influences infant gross motor skill development in the first year of life. We also found that prenatal CE and infant sex (female) were significant predictors of infant gross motor skills at 12 months of age. There was also no association found between IGF-II and infant gross motor skills. However, there was a trend towards significance as well as a large effect size when examining the relationship between prenatal exercise and cord plasma IGF-II concentrations. Our findings demonstrate that prenatal exercise, specifically when performed at higher intensities (at one month of age) and across various modes (AE, RE, CE) have a positive influence on infant gross motor skill development in the first year of life, with CE showing the greatest impact. Although we were not able to analyze cord plasma IGF-I, we observed a promising trend and large effect size between cord plasma IGF-II concentrations and prenatal exercise. Overall, these findings add to the existing literature on the benefits of prenatal exercise on infant health outcomes.