The Differential Effects of Prenatal Exercise Training Type on Maternal Glucose Metabolism: A Secondary Data Analysis of a Prospective Randomized Controlled Trial
Date of Award
Master of Science (MS)
School of Kinesiology and Recreation
Kelly R Laurson
Samantha M McDonald
Gestational diabetes mellitus (GDM) complicates 10-12% of pregnancies worldwide and poses significant, immediate, and long-term health risks to both the mom and baby. Importantly, consistent research demonstrates participating in sufficient levels of exercise during pregnancy may effectively manage maternal glucose levels, thereby potentially decreasing the risk of GDM. Most of these studies however, restricted their investigations to exposing pregnant women only to aerobic exercise. Previous studies in non-pregnant populations showed various exercise training types, such as resistance and combined (resistance + aerobic) training, elicited positive, independent effects on glucose metabolism, yet similar effects in pregnant women are unclear. PURPOSE: To evaluate differential effects of prenatal exercise training types during mid-to-late pregnancy on maternal glucose metabolism. METHODS: This study employed a secondary data analysis using data derived from a previously conducted, 24+ week prenatal exercise intervention. At 16 weeks of gestation, women were randomized to one of four groups: aerobic training (n= 89), resistance training (n= 61), combined training (n= 66), and non-exercising comparison group (n= 83). Exercise training groups participated in 3, 50-minute, moderate-intensity exercise sessions per week. The non-exercising group participated in 3, 50-minute, low-intensity stretching and breathing sessions per week. Maternal glucose metabolism was measured using fasting serum glucose levels at 16, 25-27 and 36 weeks of gestation. GDM diagnoses were extracted from medical records and determined via oral glucose tolerance tests (OGTT) performed at prenatal clinics between 25-27 weeks of gestation. Three separate ANCOVA regression models were performed to evaluate the differential effects of prenatal exercise training type on maternal glucose metabolism at 25-27 weeks (using OGTT values), 36 weeks and the change from mid-to-late pregnancy (16-36 weeks). Maternal peak oxygen consumption and pre-pregnancy body mass index served as covariates. RESULTS: Prior to randomization into intervention groups baseline measures were taken from 299 women, including, age, pre-pregnancy body mass index (BMI), race and ethnicity, relative VO2 max, and estimated 1 repetition maximum. Following baseline measures 299 women were randomized into the following: AT n= 89, RT n= 61, CT n= 66, and CON n= 83. An ITT analysis comparing the non-exercising control group at 25-27 weeks gestation, exercise training AT: 113.1 ± 3.4 mg/dL, 95% CI (106.4, 119.7), RT: 116.4 ± 5.3 mg/dL, 95% CI (105.9, 126.9), CT:113.3 ± 4.7 mg/dL, 95% CI (104.0, 122.6), CON: 115.2 ± 4.0 mg/dL, 95% CI (107.2, 123.2). Similarly, no between group differences in exercise training type were observed, AT vs. RT: -3.3 ± 6.3 mg/dL, 95% CI (-5.3,7.2), p= 1.0. AT vs CT: -0.3 ± 5.8 mg/dL, 95% CI (-6.0, 6.8), p=1.0, RT vs. CT: 3.1 ± 7.1 mg/dL, 95% CI (-7.3, 6.2), p= 1.0. Additionally, compared to the non-exercising control group at 36-weeks gestation, exercise training AT: 78.2 ± 1.5 mg/dL, 95% CI (75.1, 81.3), RT: 77.2 ± 1.7 mg/dL, 95% CI (73.7, 80.7), CT: 77.8 ± 1.8 mg/dL, 95% CI (76.1, 81.3), CON: 80.4 ± 2.2 mg/dL, 95% CI (76.1, 84.7). Likewise, no between group differences in exercise training type were observed, AT vs. RT: 1.0 ± 2.3 mg/dL, 95% CI (-7.7, 3.2), p= 1.0, AT vs. CT: 0.4 ± 2.4 mg/dL, 95% CI (-6.0, 6.8), p= 1.0 RT vs. CT: -6.0 ± 2.5 mg/dL, 95% CI (-7.3, 6.2), p= 1.0. Lastly, comparing the change in 16-week and 36-week glucose measures in the non-exercising control group, exercise training AT: -2.6 ± 1.8 mg/dL, 95% CI (-6.2, 1.0) RT: -3.6 ± 2.0 mg/dL, 95% CI (-7.7, 0.4), CT: -4.7 ± 2.2 mg/dL, 95% CI (-9.0, -0.3), CON: 0.9 ± 2.6, 95% CI (-4.2, 5.9). No between group differences in exercise training type were observed AT vs RT: 1.0 ± 2.7 mg/dL, 95% CI (6.3, 8.4), p= 1.0, AT vs. CT: 2.1 ± 1.0 mg/dL, 95% CI (-5.6, 9.8), p= 1.0, RT vs CT: 1.0 ± 3.0 mg/dL, 95% CI (-7.0, 9.1), p= 1.0 between 16-week and 36-week glucose measures. These findings were consistent for both ITT and per-protocol analysis within the sample. CONCLUSIONS: This study demonstrates that AT, RT, and CT did not elicit appreciable effects on maternal glucose metabolism in mid and late pregnancy. Despite these statistically null differences, maternal glucose values showed lower values for all exercise training types compared to the non-exercising comparison group. Our sample consisted of metabolically healthy pregnant women (7% GDM prevalence) and small number of fasted glucose samples may have inhibited the discovery of detectable differences in maternal glucose metabolism between AT, RT, and CT in this study. Future studies should consider investigating the differential effects of exercise training type among metabolically-compromised women including those at-risk or a previous history of glucose intolerance.
Prostko, Stephanie, "The Differential Effects of Prenatal Exercise Training Type on Maternal Glucose Metabolism: A Secondary Data Analysis of a Prospective Randomized Controlled Trial" (2022). Theses and Dissertations. 1567.
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