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Birth injuries are more often caused by operative deliveries, whether vaginal or abdominal than spontaneous deliveries. Birth injuries have been reported to occur in 27 of 1,000 live births, which results in 8-10 deaths in 100,000 live births. For every recorded neonatal death secondary to birth injury, 20 survivors endure permanent morbidity. Some of these injuries are preventable with proper obstetric technique.
Fractures of the clavicle (2/1,000 live births) or long bones more commonly occur with vaginal breech delivery or shoulder dystocia. Fracture of the clavicle is often heralded by an audible crack and can be confirmed by palpation or radiography after delivery. Long-bone fractures typically are less common.
Skull fractures are uncommon but should be considered with soft-tissue injury or cephalohematoma. They can sometimes be identified by palpation, but more commonly by radiography.
Facial nerve palsy usually results from pressure over the stylomastoid foramen, where the nerve exits the skull. Forceps delivery, particularly with rotation greater than 45 degrees, increases the risk of this injury.
Brachial plexus injury occurs when excessive lateral traction is applied to the fetal neck region during cephalic, breech, or cesarean birth. Injury to the upper plexus (C-5 to C-7) results in Erb's palsy with a limp arm (no Moro response) and pronation of the forearm; the grasp reflex is usually maintained. Most of these lesions are mild and responsive to conservative treatment over 3 months. Klumpke's palsy (2-3% of all nerve injuries) results from injury to the lower plexus and manifests as paralysis of the hand and wrist with absent grasp reflex. Lesions involving the C-3 to C-5 nerve roots can result in phrenic nerve paralysis and subsequent diaphragmatic and respiratory compromise.
Cephalohematomas occur in 0.2-2.5 % of live births secondary to laceration of the subperiosteal vessels by movement of the scalp soft tissues above the more rigid bone. Generally, the development of a cephalohematoma is limited to a single cranial bone (most commonly the parietal bone). Risk factors include high station, more than one pop off (vacuum extraction), fetal weight greater than 3.6 kg, instrumental delivery (particularly vacuum delivery), nulliparity, and prolonged labor. Linear skull fractures complicate 5-7% of cephalohematomas, but are generally of little long-term birth injuries.
Cerebral palsy is a nonprogressive motor disorder that may be accompanied by epilepsy, mental retardation, or both. The incidence of 1-2 in 1,000 term infants has not changed in the past 20 years. Birth asphyxia is not a significant cause for cerebral palsy. The leading predictors of cerebral palsy are maternal mental retardation, birth weight less than 2,000 g, fetal malformation, and breech presentation (but not breech delivery). Birth trauma, which is uncommon in modern obstetrics, plays a minimal role in the development of cerebral palsy. No change in the incidence of neurologic deficit has been noted over two decades, despite a reduction in the use of forceps and an increase in the rate of cesarean birth. For birth trauma to be implicated in the development of cerebral palsy, the trauma must cause intracranial bleeding, and the infant's course must include seizures and other signs of increased intracranial pressure. In most cases of cerebral palsy, the cause is unknown.