Nothing can reduce a grown man to tears faster than a shoulder dystocia! Shoulder entrapment during delivery is a true obstetric emergency that can result in significant material and infant trauma. The maternal and fetal consequences of shoulder dystocia can be devastating. Infant complication occurs in up to 20 percent of cases and includes traumatic brachial plexus injury, humeral fracture and clavicular fracture. The incidence of severe birth asphyxia and related complication is 143 per 1,000 births for delivery with SD as compared with 14 per 1,000 births for all deliveries.
I. Diagnosis: usually made only after the head has been delivered. Certain signs then appear:
1. Definite recoil of the head back against the perineum (turtle sign).
2. Because of the friction with the vulva, the head seems incapable of movement
3. The problem is usually recognized when traction from below and pressure from above fail to deliver the newborn
4. Vaginal examination is made to rule out other cause of difficulty, such as:
i. Short umbilical cord
ii. Abdominal or thoracic enlargement of the infant (malformations, neoplasm)
iii. Locked or conjoined twins
iv. Uterine constriction ring
When excessive force and lateral extension of he neck are applied during deliveries, brachial plexus injury occurs. Erb’s palsy, commonly associated with shoulder dystocia, results from injury to the firth and sixth cervical nerve roots. Some recognized risk factors for this brachial plexus palsy are fetal Macrosomia, abnormal labor, midpelvic operative delivery, maternal obesity and maternal diabetes, as identified above. Although nearly 80% of Erb’s palsies will resolved by 3-6 months of age, 1% to 5% persist one year after delivery with paralysis of the upper arm muscles and winging of the scapula.
The fact that the neurological and neonatal literature has not changed, recent obstetrical literature has been written in an attempt to help health care providers defend these cases. Over the past few years, some obstetrical researchers have published reports hypothesizing that brachial plexus injures are unpredictable and result form forces within the uterus itself. Articles by Sandmire and DeMot, Gonik, Waler and Grimm argue that it the propulsive action of the uterus stretching the nerves of the brachial plexus that cause brachial palsy injuries. They draw their conclusion from the works of other research who reviewed the records of infant who were born with brachial plexus injures and whose obstetrician or birth attendant did not document should dystocia at the time of birth. In a different retrospective review of 26,033 vaginal births n which brachial plexus injury occurs, Gonik, Hollyer and Allen concluded that shoulder dystocia was underreported because the diagnosis relies on retrospective and subjective information proceed y the clinician. The better explanation is that when the anterior arm was involved in the SD, the posterior arm was forcefully maneuvered in the delivery because the anterior arm could not be reached, thereby resulting in injury to he posterior arm.