Research has continued to demonstrate that exercise during pregnancy is safe. Growing evidence supports that exercise during pregnancy is beneficial for mother and fetus during gestation, with benefits persisting for the child into adulthood. Regardless of income or socioeconomic status, exercise during pregnancy is associated with increased incidence of full-term delivery. Additionally, normalization of birth measures, such as birth weight, occurs when women perform regular exercise throughout gestation. Measures of growth and development further indicate that exercise during pregnancy does not harm and may stimulate healthy growth throughout childhood. Measures of cognition and intelligence demonstrate that exercise during pregnancy causes no harm and may be beneficial. Overall, the benefits of exercise during pregnancy decrease the risk of chronic disease for both mother and child.

Only 50 years ago obstetric care providers and women had many concerns regarding whether exercise during pregnancy created a harmful competition for substrate resources between the fetus and the mother. Animal and human research in the past 50 years, which includes acute and chronic aerobic exercise during pregnancy, has a reassuring margin of safety throughout gestation in women. Maternal physiology adapts to pregnancy changes involving the cardiorespiratory and glucometabolic alterations. Due to these changes, pregnant women have slight differences in response to acute exercise sessions. Chronic exposure to aerobic exercise before and during pregnancy is associated with numerous maternal and neonatal adaptations which may have short- and long-term benefits to maternal and child health. On the basis of the consistent evidence of safety of exercise during pregnancy, multiple nations and health care organizations, including the American College of Obstetrics and Gynecology, recommend moderate exercise for 20 to 30 minutes most days of the week. Despite the 15 to 20 years since the first recommendations were made, only 10% to 15% of pregnant women meet this recommendation. It seems there may be 2 foci for failure to achieve these exercise recommendations: patient specific and culturally driven and/or obstetric provider not recommending regular exercise due to lack of knowledge or motivation. This article addresses the provider knowledge by a review of the normal (at rest) physiologic adaptation to pregnancy. Then, we provide a detailed description of the type and intensity of controlled experiments that document the safety of exercise during pregnancy. The short- and long-term benefits are reviewed, including the safety in moderate-risk women.

Context Maternal exercise positively influences pregnancy outcomes and metabolic health in progeny; however, data regarding the effects of different modes of prenatal exercise on offspring metabolic phenotype is lacking. Objective To elucidate the effects of different modes of maternal exercise on offspring umbilical cord derived mesenchymal stem cell (MSC) metabolism. Design Randomized controlled trial. Setting Clinical research facility. Patients Healthy females between 18 and 35 years of age and <16 weeks’ gestation. Intervention Women were randomized to either 150 minutes of moderate intensity aerobic, resistance (RE), or combination exercise per week or to a non-exercising control. Main Outcome Measures At delivery, MSCs were isolated from the umbilical cords. MSC glucose and fatty acid(s) metabolism was assessed using radiolabeled substrates. Results MSCs from offspring of all the exercising women demonstrated greater partitioning of oleate (P ≤ 0.05) and palmitate (P ≤ 0.05) toward complete oxidation relative to non-exercisers. MSCs from offspring of all exercising mothers also had lower rates of incomplete fatty acid oxidation (P ≤ 0.05), which was related to infant adiposity at 1 month of age. MSCs from all exercising groups exhibited higher insulin-stimulated glycogen synthesis rates (P ≤ 0.05), with RE having the largest effect (P ≤ 0.05). RE also had the greatest effect on MSC glucose oxidation rates (P ≤ 0.05) and partitioning toward complete oxidation (P ≤ 0.05). Conclusion Our data demonstrates that maternal exercise enhances glucose and lipid metabolism of offspring MSCs. Improvements in MSC glucose metabolism seem to be the greatest with maternal RE. Clinical Trial: ClinicalTrials.gov Identifier: NCT03838146