Specialty obstetrics ICD-9-CM 660.4 | ICD-10 O66.0 DiseasesDB 12036 | |
Shoulder dystocia is a specific case of obstructed labour whereby after the delivery of the head, the anterior shoulder of the infant cannot pass below, or requires significant manipulation to pass below, the pubic symphysis. It is diagnosed when the shoulders fail to deliver shortly after the fetal head. Shoulder dystocia is an obstetric emergency, and fetal demise can occur if the infant is not delivered, due to compression of the umbilical cord within the birth canal. It occurs in approximately 0.3-1% of vaginal births.
Contents
Signs and symptoms
One characteristic of a minority of shoulder dystocia deliveries is the turtle sign, which involves the appearance and retraction of the fetal head (analogous to a turtle withdrawing into its shell), and the erythematous (red), puffy face indicative of facial flushing. This occurs when the baby's shoulder is obstructed by the maternal pelvis.
Risk factors
About 16% of deliveries where shoulder dystocia occurs will have conventional risk factors.
There are well-recognized risk factors, such as diabetes, fetal macrosomia, and maternal obesity, but it is often difficult to predict. Despite appropriate obstetric management, fetal injury (such as brachial plexus injury) or even fetal death can be a complication of this obstetric emergency.
Maternal Risk Factors: . Age >35 . Short in stature . Small/Abnormal pelvis . Term+ (post dates) (more than 42 weeks gestation) . High maternal birthweight (macrasomia - >4000g) . Diabetes (2-4 fold increase in risk)
Factors which increase the risk/are warning signs:
Recurrence rates are relatively high (if you had shoulder dystocia in a previous delivery the risk is now 10% higher than in the general population).
Management
Management of shoulder dystocia has become a focus point for many obstetrical nursing units in North America. Courses such as the Canadian More-OB program encourage nursing units to do routine drills to prevent delays in delivery which adversely affect both mother and fetus. A common treatment mnemonic is ALARMER
The advantage of proceeding in the order of ALARMER is that it goes from least to most invasive, thereby reducing harm to the mother in the event that the infant delivers with one of the earlier maneuvers. In the event that these maneuvers are unsuccessful, a skilled obstetrician may attempt some of the additional procedures listed above. Intentional clavicular fracture is a final attempt at nonoperative vaginal delivery prior to Zavanelli's maneuver or symphysiotomy, both of which are considered extraordinary treatment measures.
Procedures
Courses that teach procedures include ALSO and PROMPT. A number of labor positions and/or obstetrical maneuvers are sequentially performed in attempt to facilitate delivery at this point, including :
More drastic maneuvers include
Complications
The major concern of shoulder dystocia is damage to the upper brachial plexus nerves. These supply the sensory and motor components of the shoulder, arm and hands. The aetiology of injury to the fetus is debated, but a probable mechanism is manual stretching of the nerves, which in itself can cause injury. Furthermore, excess tension may physically tear the nerve roots out from the neonatal spinal column, resulting in total dysfunction. The ventral roots (motor pathway) are most prone to injury, as they are in the plane of greatest tension (anterior, sensory nerves are somewhat protected due to the usual inward movement of the shoulder).
Epidemiology
Although the definition is imprecise, it occurs in approximately 0.3-1% of vaginal births.