Shoulder dystocia is a birth complication that happens when an infant’s shoulder gets caught above the mother’s pubic bone, preventing the baby from getting through the birth canal. Shoulder dystocia is considered a delivery room emergency, and obstetricians must skillfully and carefully perform certain maneuvers to ensure the birth goes well.
The baby and the mother are immediately at risk when shoulder dystocia occurs. Studies estimate that between 0.15% and 2.0% of babies experience shoulder dystocia during birth.
What is shoulder dystocia?
According to research published in the Journal of Prenatal Medicine, “[Shoulder dystocia] is defined as a delivery that requires additional obstetric maneuvers to release the shoulders after gentle downward traction has failed.”
An important indicator of possible shoulder dystocia is what’s called the turtle sign. Like a turtle pulling its head back into the shell, if a baby’s head retracts back into the birth canal after it has been delivered, doctors should be on high alert for shoulder dystocia.
The bottom line is this delivery complication requires urgent recognition and swift implementation of specific medical maneuvers to avoid injury or even death or brain damage to the baby and injury to the mother.
How common is shoulder dystocia?
This birth problem is not particularly common, but its unpredictable nature calls for medical teams to be alert and aware of the possibility of it occuring. Some estimates put the rate of shoulder dystocia in the 2%–3% range.
Most cases of shoulder dystocia happen without any warning. The absence of accurate methods for identifying the characteristics associated with this complication also makes it very hard to prevent. However, fetal weight is a factor — bigger babies are at greater risk for shoulder dystocia.
One study revealed that about 50% of the occurrences happen with babies weighing 8.8 pounds or more. For babies weighing about 9 pounds, 14 ounces, another report found the rate increases to 5% to 9%.
Shoulder dystocia is also possible for babies with lower birth weight. Shoulder dystocia shows up in 0.6% to 1.4% of infants with a birth weight between 5 pounds, 8 ounces and 8 pounds, 13 ounces born to a woman without diabetes.
Risk Factors for Shoulder Dystocia
There are telltale signs of shoulder dystocia risk. Let’s explore the risk factors:
Diabetic mother. For women with diabetes, shoulder dystocia risk is six times greater than for the non-diabetic population. Large babies of diabetic women tend to have larger shoulders, higher body fat, and larger extremity circumferences than babies of women who do not have diabetes. According to Mayo Clinic, maternal diabetes, obesity, and pregnancy weight gain are the most likely causes of macrosomia.
Macrosomia history. Women who have delivered a large baby in the past are at increased risk.
Maternal obesity. Obese women are more likely to have high birth weight infants.
Pregnancy weight. The risks for a higher-than-average baby weight increase if the mother has excessive weight gain during pregnancy.
Previous pregnancies. Because the average birth weight for each successive baby typically increases, there can be a higher risk for macrosomia with each pregnancy.
Male infants. Male babies, on average, weigh more than female babies. Babies that weigh over 9 pounds, 15 ounces are usually boys, making males more at risk for shoulder dystocia at birth.
Overdue pregnancy. Late deliveries — two weeks beyond the due date — pose a higher risk for fetal macrosomia and, potentially, shoulder dystocia.
Maternal age. Women who give birth at age 35 or older are more likely to have larger-than-average babies.
Complications of Shoulder Dystocia
Both the infant and the mother may suffer injuries and serious outcomes when the baby’s shoulder lodges above the pubic bone, making delivery difficult.
Brachial Plexus Palsy
Damage to a baby’s brachial plexus can lead to brachial plexus palsy. This condition harms the signals from the brain to the arm muscles to the extent that a baby’s arm may not work. Erb’s palsy refers to paralysis only in the shoulder and elbow. When all the muscles of the arm, hand, and wrist no longer work, the baby has a total plexus palsy.
Fractures of the collarbone are the most common newborn birth injury. These breaks in the clavicle usually come from delivery difficulties or trauma, such as an infant’s shoulder getting stuck during delivery, a narrow birth canal, or the use of tools to assist with the delivery.
When a shoulder dystocia emergency happens during birth, the mother can suffer painful injuries or conditions. These conditions can include lacerations and tearing of the perineum and cervix, issues with the symphysis, and uterine rupture.
How is shoulder dystocia diagnosed and treated?
Quickly diagnosing shoulder dystocia is key to successful intervention and treatment. Because this complication is unpredictable, careful observation during labor is mandatory.
Delivery teams must constantly monitor for any signs of shoulder dystocia.
These signs include:
- face and chin delivery struggles
- failure of the shoulders to descend
- retraction or tight contact of the head to the vulva (turtle sign)
Source: Journal of Prenatal Medicine
When these indicators are present, doctors must act and follow the prescribed first-line and second-line interventions. The medical team must avoid excessive force to the fetal head or neck and pressure on the mother’s abdomen to prevent injuries to the baby and mother.
Shoulder Dystocia Maneuvers
Although no perfect treatment exists for shoulder dystocia, a clinical tool — and mnemonic called HELPERR — provides an established framework for managing shoulder dystocia complications. In unusual cases where these actions aren’t successful, more involved options such as intentional clavicle fracture, symphysiotomy, and the Zavanelli maneuver may be needed.
A calm, skillful, and careful obstetrician is critical in these situations. They must be familiar with and able to expertly apply HELPERR.
Call for help when you suspect shoulder dystocia.
Legs. Consider using the McRoberts maneuver. This is typically the first maneuver. The medical team hyperflexes the mother’s thigh towards the abdomen to straighten the maternal sacrum. The doctor also applies pressure above the pubis.
Soprapubic pressure. Medical personnel apply downward pressure to the area above the pubis to rock the infant to try to get the shoulder in a better position for delivery. Doctors perform the soprapubic pressure technique, also known as the Rubin I maneuver, together with the McRoberts maneuver.
Enter maneuver. The “enter maneuver” is also referred to as the Rubin II maneuver. It involves the doctor using two fingers in the vagina to apply pressure to the shoulder to internally rotate the fetal shoulder to make delivery possible.
Remove the posterior arm. The goal of this maneuver is to get the posterior arm of the child delivered to facilitate full delivery. The obstetrician grasps the infant’s forearm or wrist and sweeps it across the front of the chest and out of the mother. This can then lead to delivery of the anterior shoulder trapped above the pubis.
Roll the patient. Called the Gaskin Maneuver, this action involves the obstetrics team getting the mother to her hands and knees (all fours position) or in a racing-start or sprinter position. The doctor gently applies downward traction to the baby’s posterior shoulder or upward traction to the anterior shoulder (the shoulder against the maternal symphysis).
Prognosis for Babies with Shoulder Dystocia
Doctors with more training and experience may have to deal with fewer complications from shoulder dystocia. One study found that 50% of children had full function by three months old and 82% by 18 months. As more maneuvers are employed in shoulder dystocia situations, it is more likely that a baby will suffer a brachial plexus injury (BPI). However, most BPIs heal, and less than 10% of babies sustain a permanent brachial plexus disability.