Exercise Training in Pregnancy Reduces Offspring Size without Changes in Maternal Insulin Sensitivity

• Published in: The journal of clinical endocrinology and metabolism Vol. 95; no. 5; pp. 2080 - 2088
• Main Authors: Hopkins, Sarah A., Baldi, James C., Cutfield, Wayne S., McCowan, Lesley, Hofman, Paul L.
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Oxford University Press 01.05.2010; Copyright by The Endocrine Society; Endocrine Society
• Subjects: Adult; Aerobics; Aerobiosis; Bicycling; Biological and medical sciences; Birth Weight; Blood Glucose - metabolism; Body composition; Body Mass Index; Cord blood; Endocrinopathies; Epidemiology; Exercise; Exercise - physiology; Feeding. Feeding behavior; Female; Fetal Blood - chemistry; Fetal Development - physiology; Fetuses; Fitness training programs; Fundamental and applied biological sciences. Psychology; Gestation; Humans; Infant, Newborn; Insulin; Insulin - blood; Insulin-like growth factor I; Insulin-Like Growth Factor I - metabolism; Insulin-like growth factor II; Insulin-Like Growth Factor II - metabolism; Male; Medical sciences; Neonates; Offspring; Peptides; Physical fitness; Physical training; Pregnancy; Pregnancy Trimester, Second; Pregnancy Trimester, Third; Uterus - physiology; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vertebrates: endocrinology; Physical exercise; Human; Obesity; Pancreatic hormone; Nutrition; Insulin sensitivity; Nutrition disorder; Metabolic diseases; Change; Insulin; Pregnancy; Progeny; Mother; Female; Woman; Endocrinology; Nutritional status
• ISSN: 0021-972X; 1945-7197; 1945-7197
• DOI: 10.1210/jc.2009-2255

Context: Epidemiological studies have identified the importance of the in utero environment in providing a healthy start to life. Previous studies have suggested that the maternal environment, in particular a reduction in maternal insulin sensitivity, contributes significantly to fetal growth. Regular aerobic exercise, through an effect on maternal insulin sensitivity, may influence offspring size by regulating nutrient supply to the fetus. Objective: The aim of the study was to determine the effects of aerobic exercise training in the second half of pregnancy on maternal insulin sensitivity and neonatal outcomes. Design and Setting: We conducted a community-based, randomized, controlled trial of exercise in pregnancy. Participants: Eighty-four healthy nulliparous women (mean ± sd, age, 30 ± 4 yr; body mass index, 25.5 ± 4 kg/m2) participated in the study. Intervention: Subjects participated in a home-based stationary cycling program from 20 wk gestation to delivery. Main Outcome Measures: Maternal insulin sensitivity, neonatal auxology, body composition, and growth-related peptides in cord blood were measured. Results: Offspring of exercisers had lower birth weight (sd score, control, 0.23 ± 0.8; exercise, −0.19 ± 0.9; P = 0.03) and body mass index at birth (sd score, control, 0.40 ± 0.9; exercise, −0.01 ± 0.09; P = 0.04). The reduction in maternal insulin sensitivity in late gestation was not affected by exercise (P = 0.45) and was unrelated to offspring size. Exercise offspring had lower cord serum IGF-I (P = 0.03) and IGF-II (P = 0.04). Conclusions: Regular exercise was associated with lower birth weights and reduced cord concentrations of growth-related peptides, suggesting an influence of exercise on endocrine regulation of fetal growth. These effects on offspring growth were not associated with an exercise training effect on maternal insulin sensitivity.