When macrosomia exists, shoulder dystocia is a primary obstetric concern. Current methods for estimating birth weight prior to delivery are imprecise, and macrosomia often cannot be predicted. Certain conditions or combinations of conditions should increase the index of suspicion for shoulder dystocia. When these conditions are identified, consideration should be given to the management of potential shoulder dystocia. Despite due care and appropriate clinical judgment, however, injury during the birth process cannot always be prevented.