Does the Metabolomic Profile Differ by Physical Activity Level in Pregnancy?

Introduction: Gestational physical activity (PA) is known as an effective strategy to reduce the risk of several pregnancy and birth complications, including gestational diabetes, gestational hypertension, and macrosomia. Despite the well-established health-promoting impacts of gestational PA, the underlying mechanisms behind these benefits remain poorly understood. Metabolites, which can provide a readout of the cellular, systemic metabolism, and environmental exposures, can be valuable in understanding these mechanisms. In non-pregnant individuals, there is a growing body of evidence indicating that PA leaves a signature fingerprint on the metabolome. Despite these findings, there is limited data on the metabolomic profile of the gestational parent (gesP) and no data regarding cord blood (CB) or placental metabolome associations with PA. Method: An untargeted metabolomics approach was utilized to (1) analyze the serum metabolome associations with the PA status of the pregnant individuals, (2) investigate associations between umbilical CB metabolome and gesP PA status, and (3) develop a protocol for metabolite extraction from placenta samples to enable future comprehensive analyses of gesP, CB, and placenta metabolomes responses to gestational PA. Metabolomic analysis was performed using Ultra-Performance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (Agilent Technologies Inc., Canada). Results: A total of 75 metabolites were annotated in the serum samples. Contrary to our hypothesis, the differences in measured metabolomic profiles of gesPs based on PA levels were minimal, with only pipecolic acid significantly lower in the inactive gesPs. Higher pipecolic acid and PC(18:1e/8-HEPE) emerged as potential biomarkers of lower PA status. The CB metabolome, however, displayed more pronounced differences aligned with our hypothesis. Several key metabolites, including phenylalanine, valine, threonine, lysophosphatidylcholines (18:1, 18:2, and 16:0), O-acetylcarnitine, and 5-hydroxyindole 3-acetic acid, were significantly lower in the CB of babies born to active pregnancies. Additionally, a protocol for placenta sample metabolite extraction was successfully developed, addressing challenges with solvent compatibility, extraction dilution, and the need for filtration steps. Conclusion: Higher gestational PA is associated with differences in fetal (CB) metabolome, while the effects on gesP metabolome are minimal. Gestational PA likely mitigates the risk of birth and pregnancy complications by modulating metabolic pathways that the identified metabolites are involved in. Many of these metabolites are linked to oxidative stress and inflammation, suggesting that increased PA enhances antioxidant capacity and reduces inflammation, leading to better cardiometabolic health, mainly in the fetus. Furthermore, a placenta tissue extraction protocol was designed to address the unique challenges associated with this multifunctional organ, laying the groundwork for future comprehensive investigations of gesP, CB, and placenta response to PA.