INTRODUCTION
Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance with onset or first recognition during pregnancy1. Prevalence ranges from 1 to 14% of all pregnancies, depending on the population and the diagnostic tests and criteria 1, 2. In Geneva, Switzerland, 11% of pregnant women are currently diagnosed with GDM according to the IADPSG criteria 3. Initial management of GDM consists of diet and monitoring glucose levels. When euglycemia is not achieved by diet alone, insulin therapy is prescribed 2.
There is good evidence that exercise improves insulin sensitivity in non-diabetic patients 4. The benefit of exercise is best seen in milder forms of type 2 diabetes 5, which is usually the case with GDM. A systematic review of observational studies showed that women exercising before pregnancy or in early gestation have a lower risk of GDM 6. Results of randomised trials evaluating the effects of programs in early pregnancy have shown that exercise can prevent GDM 7.
In women who develop GDM, increasing the daily time spent in moderate physical activity may be a useful therapeutic approach to improve the control of glycaemia and decrease the need for prescription of insulin. Women see the need for insulin as a failure of their initial efforts to control GDM. Injections, careful glucose monitoring and adjustment of the doses are perceived as an additional burden. Increased physical activity in pregnant women with GDM could improve the general health, decrease the risk of caesarean section, and of mother and child morbidity associated with GDM 8.
The effects of exercise programs for women diagnosed with GDM were evaluated in 11 trials including 638 women. The systematic review of these trials showed that exercise programs reduce fasting and post-prandial glycaemia, but there were no apparent benefits on clinically significant outcomes 9. One study proposing three exercise sessions per week (one supervised, two at home) suggested a reduction in insulin prescription 10. Other trials tested more intensive exercise interventions, and showed a benefit on glycaemia control 10. For many women consulting in our clinic such intensive schedules are unfeasible because of travel and time constraints. Given that in our setting women generally consult on a weekly basis, we designed a voluntary, lightweight, easily implemented and low-cost once-weekly exercise program. Our objective was to evaluate the effect of this program on insulin prescription in women with GDM.