Shoulder dystocia is an obstetric emergency that occurs when a baby's shoulder becomes trapped during vaginal childbirth. Although many cases happen without warning, certain pregnancy and delivery factors increase the risk. Prompt medical intervention is essential because prolonged obstruction can threaten the health of both the baby and mother.
Understanding shoulder dystocia during childbirth
During a typical vaginal delivery, the baby's head passes through the birth canal before the shoulders and body.
Shoulder dystocia occurs when the baby's shoulders cannot pass through normally after the head emerges.
The front shoulder may become lodged behind the mother's pubic bone.
This obstruction prevents the rest of the baby's body from being delivered with normal gentle assistance.
Healthcare professionals must act promptly to release the trapped shoulder.
The condition occurs in approximately 0.5% to 1% of vaginal deliveries, although reported rates vary depending on the definition used and the population studied.
Shoulder dystocia is difficult to predict because many affected pregnancies have no obvious warning signs.
Why shoulder dystocia happens
The condition develops when the baby's shoulders encounter an obstruction within the maternal pelvis.
A larger baby may have broader shoulders that are more difficult to deliver.
Maternal diabetes can increase the likelihood of fetal overgrowth and may affect fetal body proportions.
Other associated factors include maternal obesity, prolonged labor, a previous shoulder dystocia, and instrument-assisted vaginal delivery.
However, these circumstances do not guarantee that shoulder dystocia will occur.
The emergency can arise during deliveries that previously appeared uncomplicated.
How doctors respond to the emergency
Once shoulder dystocia is recognized, the delivery team uses established obstetric maneuvers.
The McRoberts maneuver involves bringing the mother's thighs toward her abdomen.
This changes the position of the pelvis and may help release the trapped shoulder.
Suprapubic pressure may also be applied just above the pubic bone to help reposition the baby's shoulder.
If these measures do not resolve the obstruction, clinicians may use internal rotation techniques or deliver the posterior arm.
The medical team selects and adjusts maneuvers according to the circumstances.
Excessive pulling on the baby's head or neck should be avoided because it can increase the risk of nerve injury.
Possible newborn injuries
One important complication is brachial plexus injury.
The brachial plexus is a network of nerves that controls movement and sensation in the shoulder, arm, and hand.
Damage may cause Erb's palsy, which commonly affects shoulder and elbow movement.
Shoulder dystocia may also be associated with fractures of the collarbone or upper-arm bone.
In severe cases, prolonged difficulty completing delivery may contribute to oxygen deprivation.
This can cause hypoxic-ischemic encephalopathy, a form of brain injury associated with reduced oxygen and blood flow.
However, not every episode results in injury.
Many babies recover without lasting complications.
Risks to the mother
Shoulder dystocia can also cause maternal injuries.
These may include significant vaginal or perineal tearing.
Postpartum hemorrhage is another possible complication.
The risk depends on the circumstances and severity of the delivery.
After the emergency, healthcare professionals should evaluate both the mother and baby for injuries requiring treatment.
Recovery and medical follow-up
A newborn who experiences shoulder dystocia should receive an appropriate examination.
Doctors may assess arm movement, reflexes, and possible fractures.
Persistent weakness can indicate a brachial plexus injury requiring specialist evaluation.
Some nerve injuries improve naturally.
Others require physical therapy, occupational therapy, or surgical assessment.
Follow-up helps determine whether recovery is progressing normally.
Common questions around shoulder dystocia
Can shoulder dystocia happen without warning?
Yes. Many cases occur without reliable warning signs.
Does shoulder dystocia always cause a birth injury?
No. Many babies are delivered without lasting injury.
Is shoulder dystocia always caused by medical negligence?
No. The emergency can occur despite appropriate medical care.
