Shoulder Dystocia: Symptoms, Types, Causes and Treatment

Shoulder dystocia is an unpredictable and potentially serious complication that can occur during vaginal childbirth. Recognizing, understanding, and managing this obstetric emergency is crucial for positive outcomes for both mother and baby. In this comprehensive article, you'll learn about the symptoms that signal shoulder dystocia, the different types clinicians may encounter, what causes this challenging scenario, and the step-by-step treatments that can save lives and minimize complications.

Symptoms of Shoulder Dystocia

Shoulder dystocia often presents suddenly during delivery, but its signs can be subtle if you're not prepared. Knowing the classic symptoms can help with prompt recognition and immediate intervention—essential for optimizing outcomes.

Symptom	Description	Clinical Significance	Source(s)
Turtle Sign	Fetal head retracts against the perineum after delivery	Hallmark of shoulder dystocia	5
Prolonged Delivery	Delay in delivery of shoulders (>60 seconds after the head)	Indicates impaction, need for action	5 9
Failure of Gentle Traction	Shoulders do not deliver with gentle downward traction of the fetal head	Triggers further maneuvers	5
Difficulty Delivering Face/Chin	Challenges in delivering fetal face or chin	Suggests shoulder impaction	5

Table 1: Key Symptoms

Classic Signs at the Time of Birth

The most distinctive symptom of shoulder dystocia is the "turtle sign"—the fetal head delivers, then retracts against the maternal perineum, making the neck less visible and giving the appearance of a “double chin” 5. This is a red flag for immediate action.

Diagnostic Clues for Clinicians

Other key symptoms include:

• Prolonged head-to-body delivery interval: If more than 60 seconds elapse between the delivery of the head and the rest of the body, shoulder dystocia should be strongly suspected 5 9.
• Failure of gentle traction: Normally, gentle downward pressure on the fetal head is enough to deliver the shoulders. If the shoulders don’t descend, this is a critical warning 5.
• Difficulty with face or chin delivery: Struggles in delivering the fetal face or chin can indicate that the shoulder is impacted behind the maternal pelvis 5.

Additional Observations

Some cases may also show:

• Failure of restitution: Normally, after the head is delivered, it rotates to the side (restitution). If it remains facing downward, shoulder dystocia should be considered 5.
• Lack of progress despite strong contractions: Labor appears to “stall” at the very end.

Recognizing these symptoms is vital, as delayed intervention increases the risk of complications for both mother and baby.

Types of Shoulder Dystocia

Shoulder dystocia isn't a one-size-fits-all emergency. There are variations in how and where the fetal shoulders become impacted, which can influence both recognition and the choice of maneuvers during delivery.

Type	Description	Typical Location	Source(s)
Anterior	Anterior shoulder impacted behind the pubic symphysis	Pubic symphysis	5
Posterior	Posterior shoulder impacted on sacral promontory	Sacral promontory	5
Bilateral	Both shoulders wedged in maternal pelvis	Both pelvic landmarks	5

Table 2: Types of Shoulder Dystocia

Anterior Shoulder Impaction

The most common type is where the fetal anterior shoulder becomes lodged behind the maternal pubic symphysis. This form accounts for the majority of cases and typically triggers the classic turtle sign 5.

Posterior Shoulder Impaction

Less frequently, the posterior shoulder may become stuck on the maternal sacral promontory. This can be slightly more challenging to diagnose but requires similar maneuvers for resolution 5.

Bilateral Impaction

Rarely, both shoulders can become impacted simultaneously against the maternal pelvis. This is the most severe form and may require advanced or even surgical interventions 5.

Clinical Implications

• Anterior impaction is generally easier to resolve with maneuvers such as the McRoberts maneuver and suprapubic pressure.
• Posterior or bilateral impaction often demands a broader range of techniques, including rotation or even desperate measures if standard maneuvers fail.

Understanding the specific type of shoulder dystocia can guide healthcare providers in choosing the most effective treatment approach.

Causes of Shoulder Dystocia

While shoulder dystocia is largely unpredictable, several maternal, fetal, and labor-related factors are known to increase the risk. However, it's important to remember that most cases occur without any identifiable risk factors 1 5 6 9.

Cause	Factor Description	Risk Impact	Source(s)
Fetal Macrosomia	Birth weight >4,000–4,500g	Major risk factor	1 4 5 6 7 9
Maternal Diabetes	Preexisting or gestational	Increases macrosomia risk	1 4 5 7 9
Obesity/Weight Gain	Obesity or excessive prenatal weight gain	Moderate risk	1 5 7 9
Previous Shoulder Dystocia	History of prior event	Recurrence risk ~10%	1 5 9
Operative Vaginal Delivery	Use of forceps or vacuum	Higher risk	3 5 9
Prolonged Labor	Especially second stage	Some risk	1 5 9
Post-term Pregnancy	>42 weeks gestation	Increased birth weight	5 7 9
Male Fetal Sex	Male infants	Slightly higher risk	4 5 9

Table 3: Causes and Risk Factors

Fetal Factors

• Macrosomia (large birth weight): The risk of shoulder dystocia rises sharply as fetal weight increases, especially above 4,000–4,500g 1 4 5 6 9.
• Male sex: Male babies have a slightly higher risk, possibly related to differing growth patterns 4 5 9.
• Anthropometric variations: Disproportion between fetal shoulder and head sizes can play a role 4 5.

Maternal Factors

• Diabetes (gestational or preexisting): Elevates the risk of macrosomia and shoulder dystocia, especially if blood sugar is poorly controlled 1 4 5 7 9.
• Obesity and excessive weight gain: Both increase the probability of delivering a larger baby 1 5 7 9.
• Short stature or abnormal pelvic anatomy: May contribute but are less significant than weight-related factors 5.

Labor and Delivery Factors

• Previous shoulder dystocia: The most reliable predictor, with recurrence rates of 9.8–16.7% 1 5 9.
• Operative vaginal delivery: Forceps or vacuum-assisted births are associated with higher risk 3 5 9.
• Prolonged or abnormal labor: Especially a long second stage, can increase risk 1 5 9.
• Post-term pregnancy: Going beyond 42 weeks increases the chance of macrosomia 5 7 9.

The Role of Prediction and Prevention

Despite these risk factors, shoulder dystocia is largely unpredictable and unpreventable. Most women who experience shoulder dystocia have no major risk factors 1 5 6. Prediction models and even advanced ultrasound measurements (like the TAD-BPD difference) have limited value due to low positive predictive values 4 6.

Preventative strategies are limited. Good glycemic control in diabetic pregnancies and healthy weight management may decrease risk, but induction of labor or prophylactic cesarean section is not routinely recommended except for extreme estimated fetal weights in diabetic mothers 5 6.

Treatment of Shoulder Dystocia

When shoulder dystocia occurs, time is of the essence. Rapid, systematic intervention can minimize the risk of injury to both mother and baby. The management of shoulder dystocia follows a stepwise escalation, starting with the least invasive maneuvers.

Step	Maneuver/Treatment	Purpose/Outcome	Source(s)
First-line	McRoberts maneuver, suprapubic pressure	Free the impacted shoulder	2 5 6 9 10
Second-line	Rubin, Woods screw, Gaskin, Menticoglou	Rotate/reduce shoulder diameter	5 8 9 10
Arm Delivery	Posterior arm extraction	Reduce shoulder width	5
Desperation	Clavicle fracture, Zavanelli maneuver	Last resort, high risk	5 8
Post-delivery	Hemorrhage control, neonatal exam	Address complications	3 5 10

Table 4: Treatment Steps

Initial Response and Team Preparation

• Stop maternal pushing: Prevents further impaction of the shoulder 5.
• Call for help: Multidisciplinary team involvement is crucial 5 10.
• Prepare equipment: Have resuscitation and surgical tools ready if needed 5.

First-line Maneuvers

• McRoberts Maneuver: Hyperflex the mother's legs tightly to her abdomen to rotate the pelvis and free the shoulder 2 5 6 9 10.
• Suprapubic Pressure: Apply firm pressure just above the pubic bone to dislodge the shoulder. Do not use fundal pressure, as it can worsen impaction and cause uterine rupture 5.

Both are noninvasive, effective, and easy to perform.

Second-line Maneuvers

• Rubin Maneuver: Insert fingers behind the shoulder and rotate it toward the fetal chest to decrease the diameter 5.
• Woods Screw Maneuver: Rotate the posterior shoulder in a corkscrew fashion to free the anterior shoulder 5 8.
• Gaskin Maneuver: Position the mother on all fours to widen pelvic dimensions and use gravity to assist 5.
• Menticoglou Maneuver: Downward and outward traction under the posterior axilla to deliver the shoulder 5.

Posterior Arm Delivery

• Extract the posterior arm: Flex and sweep it across the fetal chest and out of the birth canal, which decreases the shoulder width and often frees the impacted shoulder 5.

Desperation Maneuvers

If all previous steps fail:

• Intentional Clavicle Fracture: Reduces shoulder diameter but carries risks of brachial plexus injury 5.
• Zavanelli Maneuver: Replace the fetal head into the vagina and proceed with emergency cesarean section. This is a last-resort option due to high risk for both mother and baby 5 8.

After Delivery: Maternal and Neonatal Care

• Maternal: Monitor for postpartum hemorrhage, assess for lacerations (including anal sphincter injury), and manage any trauma 3 5.
• Neonatal: Immediate assessment for brachial plexus injury, fractures, and hypoxic injury is critical 1 5 10.

Importance of Documentation and Team Training

• Accurate documentation of the event, maneuvers used, timing, and outcomes is essential for legal and quality assurance reasons 1 5 10.
• Simulation and team drills improve preparedness and outcomes in real emergencies 5 10.

Conclusion

Shoulder dystocia is a rare but serious obstetric emergency that demands rapid recognition and coordinated management. While unpredictable in most cases, understanding the symptoms, types, risk factors, and treatment options is crucial for all clinicians involved in childbirth.

Key takeaways:

• Shoulder dystocia is signaled by the turtle sign, delivery delays, and failure of gentle traction 5.
• Types are classified by which shoulder is impacted—anterior, posterior, or both 5.
• Major causes include macrosomia, maternal diabetes, obesity, prior shoulder dystocia, and operative vaginal delivery, but most cases occur without risk factors 1 4 5 6 9.
• Treatment follows a stepwise escalation: McRoberts and suprapubic pressure first, then rotational and arm maneuvers, with desperation strategies as a last resort 2 5 6 8 9 10.
• Prompt, well-documented, and team-based intervention saves lives and reduces complications for mothers and babies 1 5 10.

With vigilance, preparation, and practice, the challenges of shoulder dystocia can be met successfully, ensuring the best possible outcomes for families.