Shoulder dystocia occurs in less than 1% of vaginal deliveries but it considered a medical injury and is responsible for a number of birth injuries which may lead to permanent disability.
What causes shoulder dystocia?
Shoulder dystocia occurs during a difficult vaginal birth. Once the head of the infant emerges through the birth canal, the shoulders become stuck and unable to pass the pubic bone of the mother. Shoulder dystocia is considered to be a medical emergency, placing the life of both mother and infant at risk. Once shoulder dystocia has occurred, actions taken to deliver the infant may result in injury to the infant, some of which may be permanently disabling.
Shoulder dystocia may be unpredictable but certain conditions may increase the risk including:
- large sized infant
- mother with diabetes
- multiple (twin or triplet) pregnancies
- mother is obese
- delivery past the due date
- labor induction
- prior history of shoulder dystocia
- use of forceps or vacuum tool during delivery
Shoulder dystocia cannot always be predicted, however minimizing risk factors can help prevent the occurrence. Women who are pregnant should be encouraged to maintain a healthy weight during pregnancy and control blood sugar if diabetic. If a difficult birth is expected, a cesarean section may be necessary to reduce the chance for complications including shoulder dystocia.
Signs of shoulder dystocia
Shoulder dystocia is diagnosed during delivery. One of the first signs that shoulder dystocia has occurred may be an event known as “turtling”. During delivery, once the head has been delivered, it reverses back into the birth canal like a turtle retracting its head into its shell. The baby’s head and face may also appear to be red and puffy due to an increased amount of pressure that contractions place on the infant’s body.
Once the infant’s head is delivered, the body should quickly follow. Shoulder dystocia will be diagnosed if 60 seconds pass after the head emerges and is not followed by the infant’s body. Once shoulder dystocia has been pronounced, the mother is instructed to the “4 P’s”.
She will be told to avoid:
Any of these actions can lead to further complications and increased risk of injury to both mother and infant.
Management of shoulder dystocia
Physicians and delivery room staff generally practice the “ALARMER” protocol.
A – Ask for help. The delivery room will call for additional staff as needed which may include doctors, nurses, and technicians. The mother will be given instructions and depending on the specific situation, others in the room may be enlisted to help or asked to leave.
L – Lift and hyperflex the legs. The legs of the mother will be lifted and pulled to her abdomen. The pelvic girdle may open and provide more room for the infant’s body to move through the canal. This action may be called the “McRoberts maneuver” and may be all that is needed to correct the problem.
A – Anterior shoulder disimpaction. Pressure will be placed on the abdomen to “disimpact” or free the “anterior” or front facing shoulder of the baby. In most cases, this action plus the lift and hyperflexion previously performed will be successful to free the shoulders. In the event that this does not work, disimpaction may occur manually by reaching into the vagina and dislodging the shoulder in a movement called the “Rubin maneuver”.
R – Rotate the posterior shoulder of the baby. A doctor will reach into the vagina and manually rotate the posterior or rear-facing (lower) shoulder. This is called the “Woods maneuver”.
M – Manually remove the posterior arm. The doctor may need to move the baby’s arm over the chest to deliver the infant. If required, this procedure may result in fracture of the infant’s arm. In most cases, such an injury will not lead to neurological damage or permanent disability.
E – Episiotomy. An episiotomy involves cutting of the tissue between the vagina and the anus (perineum) to enlarge the vaginal opening. In some cases, an episiotomy has already been performed but may need to be repeated or advanced.
R – Roll mother onto hands and knees. Moving the mother off of the back, onto the hands and knees may open the pelvic girdle and widen the opening to give more room for the infant to be delivered.
These procedures will be performed over a short period of time, with a space of 30 to 60 seconds allowed for each step. If unsuccessful, the routine or certain parts will be repeated until the infant is delivered.
Complications of shoulder dystocia
Shoulder dystocia can result in a number of complications for both mother and child. Once the infant is delivered, the medical team will assess the newborn and mother for injuries and complications and attend to findings. The most common maternal complications involve tearing of tissues including vaginal, cervical or uterine tissue and may involve bleeding.
Complications for the infant may be minor or much more severe. The infant may be “just fine” but he may have been subject to oxygen deprivation, decreasing blood pH levels and neurological risk. Though rare, if the dystocia lasted longer than five minutes, the risk of serious medical harm increases dramatically and can lead to oxygen deprivation which may result in a condition like cerebral palsy, neurologic or cognitive impairment or even death.
Physically, shoulder dystocia and its resolution with pulling of the infant through the birth canal may result in injuries to the neck and shoulder. In addition to a risk of a fractured arm, the brachial plexus nerve which runs through the neck and shoulder may be stretched or torn. This causes conditions like Klumpke’s palsy and Erb’s palsy which may result in loss of function of arm or hand. In most cases, both Klumpke’s and Erb’s palsy will resolve on its own in the first year but in some cases, damage and disability may be permanent.
Treatment for avoidable birth injuries is often time-consuming and costly. In some cases, the occurrence of a shoulder dystocia related condition like Klumpke’s or Erb’s palsy was an avoidable birth injury. Families of infants who had an avoidable birth injury may be eligible for compensation for medical costs, lost wages, and other expenses and should seek legal advice.