(PTFS01-03-25) A Structured Exercise Intervention in Healthy Pregnant Women With Obesity Has Minimal Effect on the Gut Microbiome

Objectives: Exercise training has been shown to alter the gut microbiome in rodent models and limited human studies; however, the effect of exercise on the gut microbiome during pregnancy is unknown. Our objective was to determine whether gut microbial ecology is affected by a structured physical activity program, consisting of aerobic and resistance exercise, in pregnant women with obesity.

Methods: Healthy pregnant women with a sedentary lifestyle and obesity (BMI ≥ 30) were enrolled in the Expecting Study (ClinicalTrials.gov NCT02125149), a randomized controlled trial investigating the effect of maternal exercise on child health outcomes. Women were randomized to receive either standard-of-care (SOC) or a structured and supervised physical activity (PA) program: 45 minutes of aerobic and strength exercises, three times a week at the Arkansas Children’s Nutrition Center (ACNC) from gestation week (GW) 13 to birth. Enrolled women provided a stool sample at GW12, GW24, and GW36. Bacterial DNA was extracted from stool (50-75 mg) using Qiagen QIAmp Fast Stool DNA Mini Kits and libraries were paired-end sequenced (2x250bp) using an Illumina MiSeq. Raw sequencing files were processed into amplicon sequence variant (ASV) counts using QIIME2.

Results: A total of 87 and 126 women in the SOC and PA groups, respectively, had stool samples available for 16S rRNA analysis. Women in the PA group increased their GW12 submaximal VO2 (workload corresponding to 15 on Borg’s scale) 9.9% by GW24, compared to a 5.5% decrease in the SOC group between GW12 and GW24 (P < 0.01). Alpha diversity estimates, total ASVs, Shannon, and Simpson indices, showed no statistical differences between PA and SOC groups across all gestational periods. Similarly, no effect of PA was observed across any gestational period for the beta-diversity estimate, Bray-Curtis Dissimilarities. Using DESeq2 and ALDEx2 workflows, only 2 ASVs were statistically different after FDR correction at GW36: An ASV classified to the Prevotella genus was lower in the PA group while an ASV classified to the Akkermansia genus was greater in the PA group relative to SOC.

Conclusions: A structured and supervised submaximal physical activity intervention improved the aerobic capacity in pregnant women with obesity, but had minimal effect on the composition of the fecal microbiota.

Funding Sources: USDA-ARS