Does Exercise Benefit GDM?
ABSTRACT & COMMENTARY
Synopsis: The authors’ exercise program did not improve maternal blood glucose levels, although it did lead to an improvement in cardiorespiratory fitness.
Source: Avery MD, et al. Obstet Gynecol 1997;89:10-15.
To determine whether a partially home-based, moderate-intensity aerobic exercise program for women with gestational diabetes mellitus (GDM) would improve glucose control, Avery et al performed a prospective randomized study of 15 women assigned to exercise and 14 control subjects. The exercise group had two supervised 30-minute sessions on a cycle ergometer at 70% of estimated maximal heart rate. These patients were also asked to exercise once or twice each week on their own, with most walking for 30 minutes. Fetal heart rate and uterine activity were monitored weekly at one supervised exercise session. Patients exercised for approximately 10 weeks. All patients performed fasting and two-hour postprandial glucose levels at home three days per week. Glycosylated hemoglobin measurements were made at four-week intervals. Dietary intake and the need for insulin therapy were also documented.
Exercise did not improve glucose control in women with GDM who exercised. No difference was noted in daily fasting or postprandial glucose levels, glycosylated hemoglobin, or the need for insulin treatment. The exercise group did experience significant improvement in cardiorespiratory fitness. No differences were noted in maternal weight gain, although control subjects had a significant daily decline of 42.6 g in carbohydrate consumption. No differences were observed in infant birth weight or the incidence of neonatal hypoglycemia.
The authors conclude that this exercise program did not improve maternal blood glucose levels, although it did lead to an improvement in cardiorespiratory fitness.
COMMENT BY STEVEN G. GABBE, MD
GDM is characterized by insulin resistance and postprandial hyperglycemia. Exercise would appear to be an ideal therapeutic approach to this problem, since it increases insulin sensitivity and leads to increased glucose uptake. In a study of supervised upper arm exercise, Jovanovic-Peterson demonstrated that women who exercised for 20 minutes, three times each week had a demonstrable improvement in glycemia after six weeks of study (Am J Obstet Gynecol 1989;161:415-419). However, the present investigation by Avery et al failed to show an improvement in maternal glucose control. As noted by the authors, the study population was small. More importantly, the investigators suggest that the study subjects may not have exercised as vigorously in their unsupervised fitness sessions.
This study does make several important points. First, as reflected in fetal heart rate and uterine contraction monitoring, exercise appeared to be safe. The most common fetal heart rate finding associated with maternal exercise was an increase in basal heart rate for 5-10 minutes. Second, exercising three or four times a week for 30 minutes did improve cardiorespiratory fitness. Since 50% or more of women with GDM will develop overt diabetes mellitus and be at greater risk for cardiovascular complications, pregnancy provides an excellent opportunity to instruct these patients in an exercise program and recommend that it be continued after delivery. While awaiting the results of further research in this area, I will continue to recommend that my patients with GDM participate in some form of aerobic exercise at least 30 minutes three times each week.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content