Sarah A. Hopkins

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

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/m(2)) 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.

Exercise in pregnancy: weighing up the long-term impact on the next generation.

There is now a large body of evidence demonstrating the influence of the in utero environment on postnatal growth. Regular aerobic exercise during pregnancy elicits maternal and fetal adaptations that seem specific to the period of gestation in which training is initiated and maintained. This review considers the evidence for both positive and negative long-term health outcomes for offspring.

Effects of exercise training on maternal hormonal changes in pregnancy

Context & Objective  A recent paper by our group reported that regular aerobic exercise during pregnancy led to lower foetal IGF‐I and IGF‐II concentrations and a modest reduction in offspring birth weight when compared with the offspring of nontraining control participants. Maternal hormonal alterations in response to exercise training may be associated with the regulation of nutrient availability for foetal growth through placental regulation of maternal metabolism.

Exercise in pregnancy: 1-year and 7-year follow-ups of mothers and offspring after a randomized controlled trial

There are limited data on long-term outcomes of mothers or their offspring following exercise interventions during pregnancy. We assessed long-term effects of an exercise intervention (home-based stationary cycling) between 20–36 weeks of gestation on anthropometry and body composition in mothers and offspring after 1 and 7 years. 84 women were randomised to intervention or usual activity, with follow-up data available for 61 mother-child pairs (38 exercisers) at 1 year and 57 (33 exercisers) at 7 years. At 1 year, there were no observed differences in measured outcomes between mothers and offspring in the two groups. At the 7-year follow-up, mothers were mostly similar, except that exercisers had lower systolic blood pressure (−6.2 mmHg; p = 0.049). However, offspring of mothers who exercised during pregnancy had increased total body fat (+3.2%; p = 0.034) and greater abdominal (+4.1% android fat; p = 0.040) and gynoid (+3.5% gynoid fat; p = 0.042) adiposity compared with controls. Exercise interventions beginning during pregnancy may be beneficial to long-term maternal health. However, the initiation of exercise during pregnancy amongst sedentary mothers may be associated with adverse effects in the offspring during childhood. Larger follow-up studies are required to investigate long-term effects of exercise in pregnancy.

Regular, moderate intensity maternal exercise reduces birth weight but increases the risk of later childhood adiposity

Methods Of the initial 84 women and their offspring who participated in the RCT, follow-up data were available on 46 mothers (26 exercisers, 20 controls) and 46 children. At each follow-up visit (6 months, 1 year, 2 years, 4 years, 6-8 years) clinical assessment included measurement of mothers’ and children’s heights, weights, BMI, and waist circumference, as well as blood pressure. Body composition was assessed in both mothers and children by whole-body dual-energy X-ray absorptiometry (DXA) scans at 4-year and 7-year follow-up visits.