However, a large multicentre randomised controlled trial hypothesised that a combined intervention of a low glycaemic diet and physical exercise may have an effect on maternal weight gain in obese women during pregnancy, reducing the incidence of GDM and large for gestational age or macrosomic babies. Unfortunately, the results of this trial indicated that the combination of diet and exercise did not have any significant effects on outcomes for obese pregnant mothers and their babies when compared to obese women following routine antenatal care, and although diet and physical activity improved, there was no effect on the incidence of GDM or macrosomic babies in the intervention group. It therefore appears that other factors may have an impact on incidence of GDM and maternal and neonatal outcomes for obese women in pregnancy.