The risk of traumatic injury and low Apgar score was studied in 473 infants with a birth weight of 4500 g or more at term (LFD) and 473 infants with normal weight (NFD, birth weight +/- 1 SD of mean for the respective gestational age). The LFD group comprised 3.2% of all infants delivered during a 5-year period. Traumatic injuries were observed in 8.0% of the LFD versus 0.6% of the NFD group. The injuries in the LFD group were 28 fractured clavicles, four fractured humerus and 12 brachial plexus injuries. Six of the LFD infants had multiple injuries. The injuries in the NFD group were three fractured clavicles. All infants with traumatic injuries were delivered vaginally. Contributory obstetrical factors for traumatic injury were forceps, post-term pregnancy and vacuum extraction. High birth weight was correlated to a low Apgar score at one minute, as also was post-term pregnancy.