Even though obese women had the lowest mean weight gain in the study group, almost half of them (44%, see Table 1) exceeded the IOM weight gain guidelines, and this group had the highest incidence of macrosomia. Obesity and weight gain above the IOM threshold increased the risk for macrosomia six-fold above that for women with normal weight who met IOM recommendations (see Table 5). A history of earlier macrosomia was also an important risk factor for recurrent macrosomia (Table 3). As such, the presence of such a history in women with GDM may represent an additional clinical opportunity to optimize maternal weight and weight gain.