An important strength of our study is the randomized design and intensive monitored weight development and repeated measures of insulin, leptin, and glucose. Time-integrated measures of the changes in the glucose metabolism could in a larger trial provide further information on how pregnancy and birth complications and are affected by alteration of the glucose metabolism. However, an important limitation for the generalization of the results from this study is the scientific settings of the trial with time-consuming extra ultrasound scans and blood samples that may also have increased the number of dropouts, favoring the recruitment of more motivated participants. Furthermore, the unrestricted control group knew they were participating in a study of maternal weight limitation. This may have influenced gestational weight gain in this group. However, this would only cause an underestimation of the effect of the intervention.