The Role of Physical Activity During Pregnancy on Metabolic Function, Inflammation, and Maternal and Neonatal Outcomes

Maternal obesity is a significant public health concern in the United States as one in three women enter pregnancy obese, and maternal obesity is associated with a large number of unfavorable maternal and neonatal outcomes. Fortunately, a physically active lifestyle during pregnancy has been shown to improve unfavorable outcomes often associated with obesity. Physical activity during pregnancy has been shown to improve maternal insulin resistance and reduce maternal gestational weight gain. In addition, neonates of physically active women have lower adiposity compared to neonates born to inactive women. Although the relationships between physical activity and maternal and neonatal outcomes are well-established, little is known about the potential for metabolic dysfunction and/or inflammation to serve as mechanisms mediating the positive impact of physical inactivity on maternal and neonatal health. Understanding mechanisms connecting maternal physical activity to improved outcomes will better inform future targeted intervention strategies.

Metabolic adaptations, specifically changes in lipid and carbohydrate metabolism, occur during normal physiologic pregnancy to provide an adequate nutrient supply to the developing fetus despite intermittent maternal dietary intake. However, in obese pregnant women these metabolic adaptations may be augmented by additional maternal metabolic dysfunction. Further, it is well-established that metabolic dysfunction in obese pregnant women has serious implications for maternal and neonatal health. Maternal substrate metabolism not only contributes to maternal health conditions such as gestational diabetes, but it also plays a major role in fetal growth and development. The "fetal origins hypothesis" suggests that an altered intrauterine metabolic environment may contribute to the programming of short and long-term neonatal outcomes.

Metabolic inflexibility may play a major role in maternal and neonatal health; however, it has not been studied during pregnancy. In non-gravid populations, physical activity is positively correlated with metabolic flexibility, and physical activity improves metabolic flexibility in lean and obese individuals.

The role of physical activity in modulating metabolic inflexibility in lean and obese pregnant women has not been studied. However, an impaired ability to switch to fat metabolism after a high-fat load is likely a better indicator of metabolic dysregulation than metabolism during resting conditions. Therefore, the current study proposes to look at the role of a physically active lifestyle on metabolic function in lean and obese pregnant women.

This project will also determine the relationships between inflammation, metabolic flexibility, and other important maternal (gestational weight gain) and neonatal (adiposity and insulin resistance) outcomes.The goal of this project is to investigate the impact of a physically-active lifestyle on inflammatory and metabolic responses to a high-fat meal in lean and obese pregnant women.