BIRTH TRAUMA BIRTH INJURY

Birth injuries to the infant resulting from mechanical forces (ie, compression, traction) during the process of birth are categorized as birth trauma. Factors responsible for mechanical injury may coexist with hypoxic-ischemic insult. One may predispose the infant to the other. Lesions that are predominantly hypoxic in origin are not discussed in this article. Significant birth injury accounts for fewer than 2% of neonatal deaths and stillbirths in this country. It still occurs occasionally and unavoidably with an average of 6-8 injuries per 1000 live births. In general, larger infants are more susceptible to birth trauma. Higher rates are reported for infants weighing more than 4500 g

Most birth traumas are self-limiting and have a favorable outcome. Nearly half are potentially avoidable with recognition and anticipation of obstetric risk factors. Infant outcome is the product of multiple factors. Separating the effects of a hypoxic-ischemic insult from those of traumatic birth injury is difficult.

Risk factors include large-for-date infants, especially larger than 4500 g; instrumental deliveries, especially forceps (midcavity) or vacuum; vaginal breech delivery; and abnormal or excessive traction during delivery.

Mortality/morbidity: Birth injuries account for fewer than 2% of neonatal deaths. From 1970-1985, rates of infant mortality resulting from birth trauma fell from 64.2 to 7.5 deaths per 100,000 live births, a remarkable decline of 88%. This decrease reflects, in part, the technologic advancements for today's obstetrician to recognize birth trauma risk factors by ultrasonography and fetal monitoring prior to attempting vaginal delivery. Use of potentially injurious instrumentation such as midforceps rotation and vacuum delivery has also declined. The accepted alternative is a cesarean delivery.

Causes: The process of birth is a blend of compression, contractions, torques, and traction. When fetal size, presentation, or neurologic immaturity complicates this event, such intrapartum forces may lead to tissue damage, edema, hemorrhage, or fracture in the neonate. The use of obstetric instrumentation may further amplify the effects of such forces or may induce injury alone. Under certain conditions, delivery by cesarean delivery can be an acceptable alternative, but it does not guarantee an injury-free birth.

Factors predisposing to injury include the following:
• Prima gravida
• Cephalopelvic disproportion, small maternal stature, maternal pelvic anomalies
• Prolonged or rapid labor
• Deep transverse arrest of descent of presenting part of the fetus
• Oligohydramnios
• Abnormal presentation (breech)
• Use of midcavity forceps or vacuum extraction
• Versions and extractions
• Very low birth weight infant or extreme prematurity
• Fetal macrosomia
• Large fetal head
• Fetal anomalies

INJURIES WITH FAVORABLE LONG-TERM PROGNOSIS
• Soft tissue
o Abrasions
o Erythema petechia
o Ecchymosis
o Lacerations
o Subcutaneous fat necrosis
• Skull
o Caput succedaneum
o Cephalhematoma
o Linear fractures
• Face
o Subconjunctival hemorrhage
o Retinal hemorrhage
• Musculoskeletal injuries
o Clavicular fractures
o Fractures of long bones
o Sternocleidomastoid injury
• Intra-abdominal injuries
o Liver hematoma
o Splenic hematoma
o Adrenal hemorrhage
o Renal hemorrhage
• Peripheral nerve
o Facial palsy
o Unilateral vocal cord paralysis
o Radial nerve palsy
o Lumbosacral plexus injury

Soft tissue injury is associated with fetal monitoring, particularly with fetal scalp blood sampling for pH or fetal scalp electrode for fetal heart monitoring, which has a low incidence of hemorrhage, infection, or abscess at the site of sampling.

Cephalhematoma
Cephalhematoma is a subperiosteal collection of blood secondary to rupture of blood vessels between the skull and the periosteum; suture lines delineate its extent. Most commonly parietal, cephalhematoma may occasionally be observed over the occipital bone.

The extent of hemorrhage may be severe enough to cause anemia and hypotension. Resolving hematoma predisposes to hyperbilirubinemia. Rarely, cephalhematoma may be a focus of infection leading to meningitis or osteomyelitis. Linear skull fractures may underlie a cephalhematoma (5-20% of cephalhematomas). Resolution occurs over weeks, occasionally with residual calcification.

No laboratory studies usually are necessary. Skull radiography or CT scanning is used if neurologic symptoms are present. Usually, management consists of observation only. Transfusion and phototherapy are necessary if blood accumulation is significant. Aspiration is more likely to increase the risk of infection. The presence of a bleeding disorder should be considered. Skull radiography or CT scanning is also used if concomitant depressed skull fracture is a possibility.

Subgaleal hematoma
Subgaleal hematoma is bleeding in the potential space between the skull periosteum and the scalp galea aponeurosis. Ninety percent of cases result from vacuum applied to the head at delivery. Subgaleal hematoma has a high frequency of occurrence of associated head trauma (40%), such as intracranial hemorrhage or skull fracture. The occurrence of these features does not correlate significantly with the severity of subgaleal hemorrhage.

The diagnosis is generally a clinical one, with a fluctuant boggy mass developing over the scalp (especially over the occiput). The swelling develops gradually 12-72 hours after delivery, although it may be noted immediately after delivery in severe cases. The hematoma spreads across the whole calvarium. Its growth is insidious, and subgaleal hematoma may not be recognized for hours. Patients with subgaleal hematoma may present with hemorrhagic shock. The swelling may obscure the fontanelle and cross suture lines (distinguishing it from cephalhematoma). Watch for significant hyperbilirubinemia. The long-term prognosis generally is good.

Laboratory studies consist of a hematocrit evaluation. Management consists of vigilant observation over days to detect progression. Transfusion and phototherapy may be necessary. Investigation for coagulopathy may be indicated.

Caput succedaneum
Caput succedaneum is a serosanguinous, subcutaneous, extraperiosteal fluid collection with poorly defined margins. It is caused by the pressure of the presenting part against the dilating cervix. Caput succedaneum extends across the midline and over suture lines and is associated with head moulding. Caput succedaneum does not usually cause complications. It usually resolves over the first few days. Management consists of observation only.

Abrasions and lacerations
Abrasions and lacerations sometimes may occur as scalpel cuts during cesarean delivery or during instrumental delivery (ie, vacuum, forceps). Infection remains a risk, but most heal uneventfully. Management consists of careful cleaning, application of antibiotic ointment, and observation. Bring edges together using Steri-Strips. Lacerations occasionally require suturing.

Subcutaneous fat necrosis
Subcutaneous fat necrosis is not usually detected at birth. Irregular, hard, nonpitting, subcutaneous plaques with overlying dusky red-purple discoloration on the extremities, face, trunk, or buttocks may be caused by pressure during delivery. No treatment is necessary. Subcutaneous fat necrosis sometimes calcifies.