The standard macrosomia definitions of 4000 or 4500 g provide a narrow window into birth weight related morbidity. For all the maternal complica-tions examined in this study, a smaller baby is better, and these improved outcomes are seen at birth weights well below 4000 g. The rates of complications begin to increase above 3500 g and continue to increase as birthweight increases. While rates of shoulder dystocia and cesarean birth jump substantially at 4000 g and again at 4500 g, the increases seen with other maternal complica- tions are slow but steady. Our standard definitions of macrosomia seem to be reasonable when applied to shoulder dystocia and cesarean birth. When considering other maternal morbidities, it is more informative to study outcomes across a range of birth weights. Confirming the findings of Boulet et al., all complications studied, except for postpar- tum infection, showed a dose—response to grades of macrosomia, with the worst outcomes seen among grade 3 (z5000 g) births.