Shoulder Dystocia

1. Clinical Overview

Summary

Shoulder Dystocia is a true obstetric emergency that occurs when the fetal head delivers but the shoulders fail to deliver spontaneously, requiring additional obstetric manoeuvres. The pathognomonic sign is the "Turtle Sign" – the delivered head retracts tightly against the maternal perineum and fails to undergo normal restitution (lateral rotation to align with the shoulders). [1,2]

The underlying mechanism in most cases is impaction of the anterior fetal shoulder behind the maternal pubic symphysis, creating a bony obstruction that cannot be relieved by episiotomy alone. This is fundamentally a mechanical problem requiring specific manoeuvres to dislodge the shoulder and permit delivery. [3]

Time is critical: umbilical cord compression between the fetal body and maternal pelvis causes progressive hypoxia, with significant risk of hypoxic-ischaemic encephalopathy (HIE) after 5-6 minutes and potential fetal death beyond 10 minutes. [4] Immediate recognition and systematic application of the HELPERR algorithm (Help, Episiotomy, Legs-McRoberts, Pressure-suprapubic, Enter-internal manoeuvres, Remove posterior arm, Roll-Gaskin) is essential. [5]

Definition

Clinical Definition: Failure of the fetal shoulders to deliver spontaneously following delivery of the head, requiring additional obstetric manoeuvres beyond routine axial traction. [1]

Objective Definition: Head-to-body delivery interval exceeding 60 seconds, or requirement for ancillary obstetric manoeuvres to achieve delivery. [6]

Epidemiology

• Incidence: 0.5-1.5% of all vaginal deliveries (higher in populations with increased maternal obesity and diabetes) [2]
• Geographic Variation: Higher rates in developed countries (1.0-1.5%) vs developing nations (0.3-0.7%) [7]
• Trend: Increasing incidence over past 30 years, correlating with rising maternal BMI and diabetes prevalence [8]

Clinical Pearls

The Turtle Sign: Pathognomonic for shoulder dystocia. After the head delivers, it immediately retracts tightly back against the maternal perineum, resembling a turtle's head withdrawing into its shell. The head fails to undergo normal restitution (lateral rotation). Recognition of this sign must trigger immediate emergency response. [1,2]

The 50/50 Rule: Approximately 50% of shoulder dystocia cases occur in infants who are NOT macrosomic (birthweight less than 4000g). This emphasizes the fundamental unpredictability of this complication – you cannot reliably prevent it through antenatal detection. [9]

NEVER Apply Fundal Pressure: Fundal pressure paradoxically INCREASES impaction of the anterior shoulder behind the pubic symphysis and significantly raises the risk of uterine rupture, brachial plexus injury, and fetal death. It is absolutely contraindicated. [5,10]

Critical Time Window: Serious fetal neurological injury becomes likely after 5-6 minutes of head-to-body delivery time. Permanent brain damage and death risk escalates rapidly beyond 10 minutes. Every manoeuvre must be performed with urgency but without panic. [4]

McRoberts + Suprapubic Pressure Solves 90%: The combination of McRoberts manoeuvre (hyperflexion of maternal thighs onto abdomen) and suprapubic pressure resolves approximately 90% of shoulder dystocia cases. These should be your first-line manoeuvres. [11]

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2. Epidemiology

Incidence and Prevalence

Temporal Trends

The incidence of shoulder dystocia has increased by approximately 30-40% over the past 3 decades, correlating with:

• Rising maternal obesity (BMI ≥30: doubled from 1990-2020) [8]
• Increasing gestational diabetes mellitus prevalence [8]
• Older maternal age at first pregnancy [7]
• Declining operative delivery rates (more vaginal deliveries attempted) [7]

Risk Factors

Antenatal Risk Factors

Intrapartum Risk Factors

Exam Detail: Why Diabetic Pregnancies Have Higher Risk at Lower Birthweights:

Infants of diabetic mothers (IDM) exhibit asymmetric macrosomia with disproportionate deposition of adipose tissue in the trunk, shoulders, and chest relative to the head. This altered fat distribution means that even at birthweights below 4000g, the bisacromial diameter (shoulder width) may be relatively larger than expected for the biparietal diameter (head size). Consequently, the head may deliver normally through the pelvis, but the shoulders encounter unexpected difficulty. [12]

This explains why shoulder dystocia risk begins at lower birthweight thresholds in diabetic pregnancies (> 3500g) compared to non-diabetic pregnancies (> 4000g), and why screening ultrasound estimated fetal weight has limited predictive value – the distribution of fetal mass matters more than absolute weight. [12]

Key Epidemiological Principle

Shoulder Dystocia is Fundamentally Unpredictable: Despite multiple identified risk factors, approximately 50% of shoulder dystocia cases occur in pregnancies with NO identifiable risk factors, and in infants with birthweight less than 4000g. [9] This has critical implications:

1. Universal Preparedness Required: All birth attendants must be trained in shoulder dystocia management
2. Routine Induction NOT Recommended: Elective induction for suspected macrosomia (EFW 4000-4500g) does NOT reduce shoulder dystocia rates and increases cesarean section rates [17]
3. Low Positive Predictive Value: Even with multiple risk factors, most deliveries will NOT experience shoulder dystocia (PPV less than 10% even in high-risk groups) [9]

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3. Pathophysiology

Normal Mechanism of Shoulder Delivery

In normal delivery, after the fetal head passes through the pelvic inlet and delivers:

1. Restitution: The head rotates laterally to realign with the shoulders
2. Descent of Shoulders: The shoulders enter the pelvic inlet in the oblique diameter
3. Anterior Shoulder Delivery: The anterior shoulder passes under the pubic arch
4. Posterior Shoulder Delivery: The posterior shoulder delivers over the perineum
5. Body Delivery: Rapid delivery of trunk and lower body follows

Mechanism of Shoulder Dystocia

Bony Obstruction

The fundamental problem is impaction of the anterior fetal shoulder behind the maternal pubic symphysis: [3]

1. Head Delivers Normally: The fetal head (biparietal diameter 9.5cm) successfully navigates through the pelvis
2. Shoulders Enter Pelvis: The bisacromial diameter (shoulder width 12-13cm in normal infant, up to 14-15cm in macrosomic infant) attempts to enter the pelvic inlet
3. Anterior Shoulder Impaction: Instead of entering in the oblique diameter, the shoulders become oriented in the anteroposterior (AP) diameter
4. Bony Obstruction: The anterior shoulder wedges behind the pubic symphysis, while the posterior shoulder may be above the sacral promontory or in the hollow of the sacrum
5. Failed Descent: Normal traction on the fetal head cannot overcome this bony obstruction

Why This is NOT a Soft Tissue Problem

This is a bony mechanical obstruction, not a soft tissue problem:

• Episiotomy Creates Access (for hands to perform internal manoeuvres) but Does NOT Solve the Impaction
• The obstruction is between fetal shoulder bone and maternal pelvic bone
• Cutting perineal soft tissue does not alter bony dimensions
• This is why episiotomy is part of HELPERR but is not therapeutic in itself [5]

Cord Compression and Hypoxic Injury

Once the head delivers but the body remains trapped:

1. Umbilical Cord Compression: The cord is compressed between the fetal thorax and maternal pelvis
2. Interruption of Gas Exchange: Placental circulation continues but umbilical flow is obstructed
3. Progressive Hypoxia: Fetal oxygen saturation drops rapidly
4. Anaerobic Metabolism: Metabolic acidosis develops
5. Critical Time Thresholds:
   • 0-5 minutes: Compensated hypoxia
   • 5-6 minutes: Decompensation begins; risk of neurological injury rises sharply [4]
   • > 10 minutes: High risk of severe HIE, permanent brain damage, or fetal death [4]

Biomechanics of McRoberts Manoeuvre

McRoberts manoeuvre works through multiple biomechanical mechanisms: [11]

1. Flattening of Lumbar Lordosis: Hyperflexion of maternal hips straightens the lumbosacral spine
2. Rotation of Symphysis Pubis: The pubic symphysis rotates cephalad by approximately 8 degrees
3. Increased Pelvic Inlet Angle: The pelvic inlet becomes more perpendicular to the direction of expulsive forces
4. Flattening of Sacral Promontory: The sacral promontory moves posteriorly, increasing the AP diameter of the inlet
5. Net Effect: The impacted anterior shoulder has more space to pass under the pubic arch

Studies using X-ray pelvimetry demonstrate that McRoberts increases the functional AP diameter of the pelvic inlet by approximately 1-2cm. [11]

Biomechanics of Suprapubic Pressure

Suprapubic pressure (vs contraindicated fundal pressure): [10]

Suprapubic Pressure (Correct):

• Pressure applied downward and posteriorly from above the pubic symphysis
• Pushes on the anterior aspect of the impacted anterior shoulder
• Adducts the shoulders (brings them closer together), reducing bisacromial diameter
• May dislodge the anterior shoulder from behind the pubic symphysis
• Can be applied continuously or in a rocking motion (CPR-like)

Fundal Pressure (CONTRAINDICATED):

• Pushes the entire fetus downward
• INCREASES impaction of anterior shoulder behind pubis
• Dramatically increases risk of:
  • Brachial plexus injury (excessive lateral traction reflex) [10]
  • Uterine rupture (especially in scarred uterus) [10]
  • Fetal death [10]

Why Diabetic Babies are Different (Pedersen Hypothesis)

The Pedersen Hypothesis explains altered fetal growth in diabetic pregnancy: [12]

1. Maternal Hyperglycemia → Fetal hyperglycemia
2. Fetal Pancreatic Hyperplasia → Fetal hyperinsulinemia
3. Insulin as Growth Factor → Preferential deposition of adipose tissue in insulin-sensitive regions:
   • Trunk (chest, abdomen)
   • Shoulders (subscapular fat)
   • Cheeks (facial fat)
4. Head Growth Normal (brain is not insulin-sensitive)
5. Result: Asymmetric macrosomia with relatively large trunk/shoulders compared to head

This asymmetry means:

• Standard ultrasound estimation of fetal weight (based on head circumference, femur length, abdominal circumference) may underestimate shoulder diameter
• Risk of shoulder dystocia is elevated even at lower birthweights (> 3500g in diabetic vs > 4000g in non-diabetic)
• The head-to-shoulder disproportion is the critical factor, not absolute weight [12]

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4. Clinical Presentation

Recognition of Shoulder Dystocia

Shoulder dystocia is a clinical diagnosis made in real-time during delivery.

Pathognomonic Sign: The Turtle Sign

Description: After the fetal head delivers, it immediately retracts tightly back against the maternal perineum, resembling a turtle's head withdrawing into its shell. [1,2]

Mechanism: The impacted shoulders are pulling the head back toward the pelvis. The nuchal tissue is stretched taut.

Critical Feature: The head does NOT undergo restitution (the normal lateral rotation to realign with the fetal shoulders in the pelvis).

Recognition: This is the definitive "call for help" moment. The turtle sign is 100% specific for shoulder dystocia.

Clinical Features at Recognition

Timing and Urgency

Once shoulder dystocia is recognized, a silent clock starts: [4]

Differential Diagnosis of Delayed Shoulder Delivery

Not every delayed shoulder delivery is shoulder dystocia:

Exam Detail: Viva Question: "The fetal head delivers but the shoulders don't follow immediately. How do you differentiate shoulder dystocia from a tight nuchal cord?"

Model Answer:

"The key distinguishing feature is the turtle sign. In true shoulder dystocia, the delivered head immediately retracts tightly back against the maternal perineum and fails to restitute (rotate laterally). This indicates bony impaction of the anterior shoulder behind the pubic symphysis.

In contrast, with a tight nuchal cord preventing descent, the head typically does NOT retract in the same manner. You may see the cord visibly wrapped tightly around the neck, and there may be some head descent limitation, but the pathognomonic turtle sign is absent. Management differs: for nuchal cord, you can attempt a somersault manoeuvre (tucking the chin and delivering the body through the loop) or, if extremely tight, clamp and cut the cord. For shoulder dystocia, you immediately activate the HELPERR algorithm.

The critical error would be mistaking a tight nuchal cord for shoulder dystocia and applying aggressive manoeuvres unnecessarily, or conversely, failing to recognize true shoulder dystocia and delaying appropriate intervention."

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5. Investigations

During Acute Event

NO investigations are performed during the acute emergency. Shoulder dystocia is a clinical diagnosis requiring immediate intervention.

All effort is directed toward:

1. Recognition (turtle sign)
2. Calling for help
3. Systematic application of manoeuvres (HELPERR)
4. Delivery of the baby

Post-Delivery Assessment

Immediate Neonatal Assessment

Specific Neonatal Injuries to Assess

Maternal Assessment

Documentation Requirements

Medico-legal considerations: Shoulder dystocia is a high-risk event for litigation. Meticulous documentation is essential: [18]

1. Time of Recognition: Exact time turtle sign observed
2. Time of Head Delivery: Document head-to-body interval
3. Manoeuvres Performed: Each manoeuvre attempted, in sequence
4. Time Each Manoeuvre Started: Allows reconstruction of timeline
5. Personnel Present: Names and roles of all attendants
6. Assistance Called: Who was called, when they arrived
7. Neonatal Outcome: Apgar scores, cord gases, injuries identified
8. Maternal Outcome: Blood loss, perineal trauma, complications
9. Debrief Offered: Documentation that debrief was offered to parents

Use of Scribe: Ideally, a dedicated scribe should document in real-time during the emergency. If not possible, documentation should be completed immediately after the event while details are fresh. [18]

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6. Management

Emergency Response Protocol

Shoulder dystocia management is time-critical and follows the HELPERR Mnemonic: [5]

         SHOULDER DYSTOCIA RECOGNIZED
         (TURTLE SIGN - Head Retracts, No Restitution)
                      ↓
    ═══════════════════════════════════════════════
                   START TIMER
                 CALL FOR HELP
    ═══════════════════════════════════════════════

HELPERR Algorithm (Detailed)

H – HELP

IMMEDIATE ACTION: Activate emergency protocol

Who to call:

• Senior obstetrician (consultant if available)
• Additional midwives (minimum 2 assistants needed)
• Anaesthetist (for potential maternal complications or last-resort procedures)
• Neonatal team (senior pediatrician/neonatologist for resuscitation)
• Theatre team (alert for potential Zavanelli + Emergency C-section)

Assign roles:

• Lead obstetrician: Directs manoeuvres
• Assistant 1: Performs McRoberts (holds leg)
• Assistant 2: Performs McRoberts (holds other leg) + suprapubic pressure
• Scribe: Documents timing and manoeuvres in real-time
• Neonatal team: Prepares for resuscitation
• Anaesthetist: Standby for complications

DO NOT DELAY further action while waiting for help to arrive.

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E – EPISIOTOMY

Purpose: Create space for operator's hand to enter vagina and perform internal manoeuvres

Technique:

• Mediolateral episiotomy (UK practice) or median episiotomy (US practice)
• Cut if not already present or extend if inadequate

Critical Understanding:

• Episiotomy DOES NOT solve the bony impaction
• It DOES provide access for internal manoeuvres (Rubin, Woods Screw, posterior arm)
• DO NOT delay McRoberts to perform episiotomy – episiotomy can be done simultaneously or after McRoberts if access is needed

Common Error: Assuming episiotomy alone will solve shoulder dystocia. It will not.

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L – LEGS (McROBERTS MANOEUVRE)

FIRST-LINE MANOEUVRE – Solves 40-50% of cases alone, 90% when combined with suprapubic pressure [11]

Technique:

1. Remove legs from stirrups (if present)
2. Two assistants each hold one leg
3. Hyperflex maternal hips onto maternal abdomen (knees to chest position)
4. Flatten lumbar lordosis (maternal buttocks remain on bed)
5. Hold position continuously while applying gentle downward traction on fetal head

Biomechanical Effect: [11]

• Rotates pubic symphysis cephalad
• Flattens sacral promontory
• Increases pelvic inlet angle
• Creates 1-2cm additional AP diameter at inlet
• Facilitates anterior shoulder passage under pubic arch

Duration: Hold for 30-60 seconds while attempting delivery

Key Point: This is a maternal positional manoeuvre, not a fetal manipulation

Common Error: Inadequate hyperflexion – thighs must be maximally flexed onto abdomen, not just elevated

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P – PRESSURE (SUPRAPUBIC PRESSURE)

Used in combination with McRoberts

Technique:

Continuous Pressure:

1. Assistant identifies fetal back position (anterior shoulder is on same side as fetal back)
2. Place heel of hand above pubic symphysis on the side of fetal back
3. Apply firm downward and posterior pressure
4. Maintain for 30-60 seconds

OR

Rocking/CPR-like Pressure:

1. Same hand position
2. Apply intermittent firm pressure in rocking motion (similar to CPR compressions)
3. Rhythm: 30 compressions over 30 seconds

Biomechanical Effect:

• Pushes posterior aspect of anterior shoulder
• Adducts shoulders (reduces bisacromial diameter)
• May dislodge anterior shoulder from behind pubis

Assistant Coordination: One assistant performs suprapubic pressure while two others maintain McRoberts position

CONTRAINDICATION: FUNDAL PRESSURE IS ABSOLUTELY CONTRAINDICATED [10]

• Fundal pressure pushes the entire fetus downward
• INCREASES impaction of anterior shoulder
• Dramatically increases risk of:
  • Brachial plexus injury
  • Uterine rupture
  • Fetal death

McRoberts + Suprapubic Pressure: This combination resolves approximately 90% of shoulder dystocia cases. [11] If unsuccessful after 30-60 seconds, proceed immediately to internal manoeuvres.

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E – ENTER (INTERNAL MANOEUVRES)

SECOND-LINE – If McRoberts + Suprapubic Pressure unsuccessful

These manoeuvres require the operator's entire hand to enter the vagina (this is why episiotomy is important for access).

Rubin II Manoeuvre

Objective: Adduct the shoulders to reduce bisacromial diameter

Technique:

1. Identify position of fetal back (anterior shoulder is on same side as back)
2. Insert hand into vagina posteriorly (behind fetal posterior shoulder is easier access)
3. Locate anterior shoulder
4. Place fingers on POSTERIOR aspect of anterior shoulder (the aspect facing the fetal chest)
5. Push toward fetal chest (adducting the shoulder)
6. This reduces bisacromial diameter and may dislodge shoulder from behind pubis

Mnemonic: "Push on the most accessible part of the most difficult shoulder" (push on back of anterior shoulder)

Alternative: Reverse Rubin – Push on anterior aspect of posterior shoulder (also adducts)

Woods Screw Manoeuvre

Objective: Rotate the fetus 180 degrees to bring the posterior shoulder anteriorly (like unscrewing a corkscrew)

Technique:

1. Insert hand into vagina
2. Locate posterior shoulder
3. Place fingers on ANTERIOR aspect of posterior shoulder (the aspect facing away from fetal chest)
4. Push circumferentially to rotate the posterior shoulder anteriorly through 180-degree arc
5. As posterior shoulder rotates to become the new anterior shoulder, it is delivered first under the pubic arch
6. The original impacted anterior shoulder (now rotated to posterior position) is delivered over the perineum

Mnemonic: "Screw the baby out like a corkscrew"

Alternative: Reverse Woods Screw – Rotate in opposite direction

Common Error: Attempting rotation without adequate space (episiotomy required)

Combination: Rubin + Woods

These manoeuvres can be combined:

• Attempt Rubin II (adduction) while simultaneously attempting rotational movement
• If one direction of rotation fails, try the opposite direction

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R – REMOVE POSTERIOR ARM

HIGHLY EFFECTIVE manoeuvre when internal rotations fail

Technique:

1. Insert hand into vagina along fetal posterior shoulder
2. Follow the posterior arm down to the fetal elbow
3. Flex the elbow (bringing forearm across fetal chest)
4. Sweep the forearm across the fetal chest and out through the vagina
5. Grasp the hand/wrist and deliver the posterior arm first
6. With posterior arm delivered, bisacromial diameter is effectively reduced to shoulder-to-chest diameter
7. Fetus can now rotate and anterior shoulder delivers easily

Biomechanical Effect: Removing posterior arm reduces obstruction and allows rotation

Risk:

• Humerus or clavicle fracture (~5-10% risk) [5]
• However, fractures heal well and this is far preferable to fetal death or permanent neurological injury

Common Error: Difficulty finding/reaching posterior arm. Adequate episiotomy and maternal position (McRoberts) improves access.

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R – ROLL (GASKIN MANOEUVRE / ALL-FOURS POSITION)

Alternative Positional Manoeuvre

Technique:

1. Assist mother to hands-and-knees position (all-fours)
2. This may not be possible if epidural in situ
3. Attempt delivery in this position

Biomechanical Effect:

• Changes pelvic dimensions and angles
• Gravity assists
• May dislodge impacted shoulder

Success Rate: Variable (reported 40-80%) [5]

Practical Limitations:

• Difficult with epidural analgesia (maternal mobility limited)
• Requires cooperation from exhausted mother
• Not possible if mother cannot move

Role: Consider if internal manoeuvres unsuccessful, or as alternative first-line in home birth settings

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Last-Resort Manoeuvres

If all above manoeuvres fail (rare), consider:

Zavanelli Manoeuvre + Emergency Caesarean Section

Technique:

1. Restitute the fetal head to occipito-anterior position
2. Flex the head (reverse the extension that occurred at delivery)
3. Push the head back into the vagina by applying pressure on fetal face/occiput
4. Maintain head in vagina manually
5. Immediate Emergency Caesarean Section under general anaesthesia
6. Deliver baby abdominally

Success Rate: ~90% when performed correctly [5]

Requirement: Immediate access to theatre and anesthesia

Risk: Uterine rupture, fetal injury

Indication: All other manoeuvres failed and fetal compromise severe

Symphysiotomy

Technique: Surgical division of pubic symphysis to increase pelvic diameter

Indication: Resource-limited settings where emergency C-section not available

Rarely performed in developed countries

Complications: Permanent maternal orthopedic morbidity

Cleidotomy

Technique: Deliberate fracture or division of fetal clavicle to reduce shoulder diameter

Indication: Fetal demise already occurred, or as alternative to Zavanelli

Risk: Difficulty accessing clavicle; risk of injury to vessels

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Management Algorithm Summary

Most cases resolve with McRoberts + Suprapubic Pressure (90%). [11]

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What NOT to Do (Critical Contraindications)

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Post-Delivery Immediate Actions

1. Hand baby to neonatal team for immediate assessment and resuscitation if needed
2. Deliver placenta (active management; may have increased risk of PPH)
3. Assess perineal trauma (high rate of 3rd/4th degree tears)
4. Estimate blood loss (PPH common)
5. Uterine palpation (ensure contracted; risk of atony)
6. Document meticulously (timing, manoeuvres, personnel, outcome)
7. Offer immediate debrief to parents (once baby stabilized)

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Exam Detail: OSCE Station: Shoulder Dystocia Management Drill (Mannequin)

Scenario: You are the midwife/doctor attending a normal delivery. The head has just delivered, but with the next push, the head retracts tightly against the perineum and does not restitute. Manage this emergency.

Expected Actions (Marking Criteria):

1. Recognition (2 points)

   • Identifies "Turtle Sign"
   • States "This is shoulder dystocia"

2. H – Help (3 points)

   • Calls for help urgently (says "I need help for shoulder dystocia")
   • Requests senior obstetrician, additional midwives, neonatal team, anaesthetist
   • Assigns scribe to document timing

3. E – Episiotomy (2 points)

   • States "I will perform/extend episiotomy to create access"
   • Does not delay McRoberts for episiotomy

4. L – Legs (McRoberts) (4 points)

   • Instructs assistants to remove legs from stirrups
   • Instructs "Hyperflex hips onto abdomen"
   • Demonstrates/describes adequate hyperflexion
   • States "Hold this position"

5. P – Pressure (4 points)

   • Identifies fetal back position
   • Instructs assistant to apply suprapubic pressure
   • Describes correct location: "Above pubic symphysis, on side of fetal back"
   • Describes correct direction: "Downward and posterior"
   • States "NO fundal pressure"

6. E – Enter (Internal Manoeuvres) (5 points)

   • States "If unsuccessful after 30-60 seconds, I will perform internal manoeuvres"
   • Describes Rubin II: "Insert hand, locate posterior aspect of anterior shoulder, push toward fetal chest"
   • OR describes Woods Screw: "Rotate posterior shoulder anteriorly 180 degrees"

7. R – Remove Posterior Arm (4 points)

   • States "If rotations unsuccessful, I will deliver posterior arm"
   • Describes: "Insert hand along posterior shoulder, flex elbow, sweep forearm across chest, deliver hand first"

8. R – Roll (2 points)

   • Mentions Gaskin/all-fours as alternative

9. Post-Delivery (4 points)

   • Hands baby to neonatal team
   • States will assess for brachial plexus injury, fractures
   • States will obtain cord gases
   • States will document meticulously

10. Communication (2 points)

    • Calm, clear, directive communication
    • Reassures mother (if appropriate)

Total: 32 points

Pass Mark: 24/32 (75%)

Common Failures:

• Applying fundal pressure (automatic fail)
• Excessive traction on head without manoeuvres (fails safety)
• Cannot describe McRoberts correctly
• Does not call for help urgently
• Incorrect suprapubic pressure technique (pushes on fundus)

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7. Complications

Fetal/Neonatal Complications

Brachial Plexus Injury (Erb's Palsy)

Incidence: 10-15% of shoulder dystocia cases [10]

Mechanism:

• Excessive lateral traction or lateral flexion of fetal head/neck during delivery attempts
• Stretches the upper roots of brachial plexus (C5-C6, ± C7)
• Can occur even with appropriate manoeuvres (not always preventable)
• Risk increased with fundal pressure or excessive traction

Clinical Presentation:

• Erb's Palsy (C5-C6): Most common
  • Absent Moro reflex on affected side
  • "Waiter's Tip" posture: Shoulder adducted and internally rotated, elbow extended, forearm pronated, wrist flexed
  • Absent biceps and brachioradialis reflexes
  • Preserved hand grasp (C8-T1 intact)
• Klumpke's Palsy (C8-T1): Rare
  • Weakness of hand and wrist flexors
  • Claw hand deformity
  • Horner's syndrome if T1 involved
• Total Plexus Injury (C5-T1): Entire arm flaccid

Prognosis: [10]

• 70-90% recover fully within 12 months
• 10-30% have persistent weakness
• 5-10% have permanent significant disability
• Factors favoring recovery: Partial injury, early return of function (within 2 weeks)

Management:

• Immediate pediatric/neonatal assessment
• Neurology referral
• Physiotherapy (passive range of motion to prevent contractures)
• Surgical nerve repair/grafting if no recovery by 3-6 months

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Fractures

Management:

• X-ray confirmation
• Immobilization (clavicle: no specific treatment; humerus: splinting)
• Parental reassurance (excellent prognosis)
• Orthopedic follow-up

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Hypoxic-Ischaemic Encephalopathy (HIE)

Incidence: 1-2% of shoulder dystocia cases (higher if prolonged head-to-body interval > 6 minutes) [4]

Mechanism: Umbilical cord compression → fetal hypoxia → ischemic brain injury

Severity Grading (Sarnat Staging):

• Mild (Grade I): Hyperalert, jittery, normal outcome
• Moderate (Grade II): Lethargic, hypotonic, seizures; 20-30% abnormal outcome
• Severe (Grade III): Stupor/coma, apnea, absent reflexes; 50-75% death or severe disability

Risk Factors for HIE:

• Head-to-body interval > 6 minutes [4]
• Severe acidosis (umbilical artery pH less than 7.0, base excess -16 or less)
• Apgar score less than 5 at 10 minutes

Management:

• Therapeutic hypothermia (cooling to 33-34°C for 72 hours) if moderate-severe HIE [4]
• NICU admission
• Anti-epileptic drugs for seizures
• Supportive care

Prognosis: Dependent on severity; cooling improves outcomes in moderate HIE

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Stillbirth / Neonatal Death

Incidence: less than 1% with prompt, trained management; higher (5-10%) if prolonged or mismanaged [2,4]

Risk Factors:

• Head-to-body interval > 10 minutes
• Absence of trained personnel
• Application of fundal pressure (increases mortality)

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Maternal Complications

Postpartum Hemorrhage (PPH)

Incidence: 10-15% (higher than baseline ~5%) [15]

Mechanism:

• Prolonged labor → uterine atony
• Operative manoeuvres → genital tract trauma
• Uterine rupture (if fundal pressure applied)

Management: Standard PPH protocol (uterotonic drugs, bimanual compression, balloon tamponade, surgical intervention if needed)

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Perineal Trauma (3rd and 4th Degree Tears)

Incidence: 5-10% (higher if episiotomy + manoeuvres) [15]

Risk Factors:

• Episiotomy (mediolateral or median)
• Posterior arm delivery (sweeping across perineum)
• Large baby

Management: Immediate recognition and surgical repair in theatre by experienced operator

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Uterine Rupture

Incidence: Rare (less than 1%) but devastating

Risk Factor: Fundal pressure (absolute contraindication) [10]

Presentation: Sudden severe abdominal pain, hemorrhage, fetal distress, maternal shock

Management: Emergency laparotomy, repair or hysterectomy

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Psychological Trauma / PTSD

Incidence: 20-30% report traumatic experience; 5-10% meet criteria for PTSD [18]

Risk Factors:

• Poor communication during emergency
• Lack of explanation/debrief afterward
• Adverse neonatal outcome (HIE, Erb's palsy)
• Feeling of loss of control

Management:

• Immediate debrief after event (once mother and baby stable)
• Explanation of what happened and why
• Opportunity to ask questions
• Written documentation provided to parents
• Follow-up in postnatal period
• Referral to psychology/counseling if PTSD symptoms develop

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Exam Detail: Viva Question: "What are the major fetal complications of shoulder dystocia, and how can they be minimized?"

Model Answer:

"The major fetal complications of shoulder dystocia are:

1. Brachial Plexus Injury (10-15%), most commonly Erb's palsy affecting C5-C6 roots, presenting as 'waiter's tip' posture with absent Moro reflex. Risk is minimized by:

• Avoiding excessive lateral traction on the fetal head
• Using systematic manoeuvres (HELPERR) rather than force
• Absolutely avoiding fundal pressure
• Good training and simulation drills However, it's important to note that brachial plexus injury can occur even with appropriate manoeuvres, as the impaction itself creates traction forces. Approximately 70-90% recover fully within 12 months.

2. Fractures (Clavicle 5-10%, Humerus 1-5%), which generally have excellent prognosis with spontaneous healing. These may be iatrogenic during appropriate manoeuvres (such as deliberate cleidotomy or during posterior arm delivery) and are acceptable when weighed against risk of fetal death.

3. Hypoxic-Ischaemic Encephalopathy (1-2%), which occurs due to cord compression between fetal body and maternal pelvis. Risk increases sharply after 5-6 minutes of head-to-body delivery time. Minimization strategies:

• Immediate recognition of turtle sign
• Rapid systematic application of HELPERR manoeuvres without delay
• Avoiding time-wasting actions like excessive traction
• Ensuring all delivery staff are trained through simulation (ALSO/PROMPT)

4. Stillbirth/Death (less than 1% with appropriate management), which is the most catastrophic outcome but rare when manoeuvres are performed promptly and correctly.

The key principle is that the complications of appropriate, timely manoeuvres are far preferable to the complications of prolonged impaction (death or permanent brain injury). Documentation and parental debrief are essential given the medico-legal and psychological implications."

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8. Prognosis and Outcomes

Immediate Outcomes

With prompt recognition and trained management:

• > 99% of babies survive [2]
• ~90% deliver with McRoberts + Suprapubic Pressure alone [11]
• Majority have no long-term complications

Adverse outcomes strongly correlate with:

• Delay in recognition
• Head-to-body delivery interval > 6 minutes [4]
• Absence of trained personnel
• Application of fundal pressure [10]

Long-Term Neonatal Outcomes

Recurrence Risk in Subsequent Pregnancies

Recurrence Rate: 10-15% in subsequent vaginal delivery [13]

Risk Factors for Recurrence:

• Birthweight of subsequent baby (higher risk if ≥4000g)
• Maternal diabetes
• Severity of initial shoulder dystocia (prolonged, multiple manoeuvres)

Counseling for Future Pregnancies

After shoulder dystocia, counsel regarding options for next pregnancy: [13]

Option 1: Trial of Vaginal Delivery (Supervised)

Considerations:

• 85-90% will NOT have recurrence
• Requires informed consent
• Delivery should occur in hospital with experienced staff immediately available
• Continuous monitoring
• Preparedness for shoulder dystocia (HELPERR protocol ready)

Relative Contraindications:

• Previous severe shoulder dystocia (prolonged, severe neonatal injury)
• Estimated fetal weight ≥4500g
• Maternal diabetes with EFW ≥4000g

Option 2: Elective Caesarean Section

Indications:

• Maternal preference after full counseling
• Previous severe shoulder dystocia with adverse neonatal outcome
• EFW ≥4500g (non-diabetic) or ≥4000g (diabetic) [17]
• Multiple previous episodes

Discussion: CS eliminates risk of recurrent shoulder dystocia but carries surgical risks (bleeding, infection, VTE, future placenta previa/accreta)

Maternal Psychological Outcomes

• Traumatic Birth Experience: 20-30% report the delivery as traumatic [18]
• Post-Traumatic Stress Disorder (PTSD): 5-10% [18]
• Fear of Childbirth (Tokophobia): May impact decision for future pregnancies
• Management:
  • Immediate debrief after delivery
  • Written explanation of events
  • Postnatal follow-up to discuss concerns
  • Referral to perinatal mental health services if PTSD symptoms
  • Pre-conception counseling for future pregnancy
  • Birth planning for subsequent delivery (discuss mode of delivery, venue, staff)

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9. Prevention and Risk Reduction

Primary Prevention (Population Level)

Secondary Prevention (Antenatal Interventions)

Elective Induction of Labor for Suspected Macrosomia

Evidence: [17]

• Non-Diabetic Women: Routine induction for EFW 4000-4500g does NOT reduce shoulder dystocia or neonatal injury
• Increases cesarean section rate without benefit
• NOT recommended by ACOG or RCOG
• Exception: May consider for EFW ≥4500g (balanced discussion of risks/benefits)

Diabetic Women:

• Earlier delivery (38-39 weeks) recommended to reduce macrosomia
• Threshold for CS lower (EFW ≥4000g may prompt discussion)

Prophylactic Cesarean Section

Indications:

• EFW ≥4500g in non-diabetic women (ACOG) [17]
• EFW ≥4000g in diabetic women (consider; not absolute) [17]
• Previous severe shoulder dystocia with poor outcome
• Maternal preference after informed consent

Limitation: Ultrasound EFW has wide confidence intervals (±15-20%); many unnecessary CS would be performed to prevent one shoulder dystocia

Tertiary Prevention (Intrapartum Recognition and Preparedness)

Most Effective Strategy: Universal Training in Shoulder Dystocia Management

Simulation Training (ALSO / PROMPT Programs)

Evidence: [19]

• Regular simulation ("drills") significantly improves:
  • Recognition speed
  • Manoeuvre performance
  • Team coordination
  • Neonatal outcomes (reduced brachial plexus injury)
• PROMPT (PRactical Obstetric Multi-Professional Training): Structured simulation course
• ALSO (Advanced Life Support in Obstetrics): Includes shoulder dystocia module

Recommendation: All maternity units should conduct regular shoulder dystocia drills (every 6-12 months) [19]

Equipment and Protocols

• McRoberts position aids (leg holders with quick-release)
• Shoulder dystocia emergency stickers/stamps for documentation
• Algorithmic posters (HELPERR) visible in delivery rooms
• Emergency call system for rapid team assembly

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10. Evidence and Guidelines

International Guidelines

RCOG Green-Top Guideline No. 42 (2012, Updated 2017) [1]

Key Recommendations:

• Shoulder dystocia is unpredictable; all staff must be trained
• HELPERR algorithm should be followed systematically
• McRoberts + Suprapubic Pressure are first-line manoeuvres
• Fundal pressure is contraindicated
• Routine induction for suspected macrosomia (EFW 4000-4500g) NOT recommended
• Consider CS for EFW ≥4500g (non-diabetic) or ≥4000g (diabetic)
• Regular multi-professional training (simulation drills) should be conducted
• Meticulous documentation and parental debrief are essential

ACOG Practice Bulletin No. 178 (2017) [17]

Key Recommendations:

• Predictive models for shoulder dystocia have poor positive predictive value
• Induction of labor for suspected macrosomia in non-diabetic women is NOT recommended
• Prophylactic CS may be considered for EFW ≥5000g (non-diabetic) or ≥4500g (diabetic)
• Training in shoulder dystocia is essential for all delivery providers
• Avoid excessive downward traction on fetal head
• Document all manoeuvres and timing

WHO Recommendations (2018)

• Shoulder dystocia is a medical emergency requiring immediate action
• All birth attendants should be trained in basic manoeuvres
• Simulation training improves outcomes

Landmark Evidence

McRoberts Manoeuvre – Gherman et al. (2000) [11]

Study: X-ray pelvimetry analysis of McRoberts position

Findings:

• McRoberts increases pelvic inlet angle by 8 degrees
• Flattens sacral promontory
• Increases functional AP diameter of inlet by 1-2cm
• Reduces bony obstruction to shoulder passage

Impact: Established McRoberts as first-line positional manoeuvre

PROMPT Training – Draycott et al. (2008) [19]

Study: Before-and-after study of multi-professional simulation training

Findings:

• Introduction of regular PROMPT drills reduced:
  • Brachial plexus injury rate (from 9.3 to 2.3 per 1000 births)
  • Hypoxic-ischaemic encephalopathy rate
• Improved team performance and communication

Impact: Strong evidence for mandatory simulation training

Fundal Pressure Contraindication – Gross et al. (1987) [10]

Study: Case series analysis of shoulder dystocia outcomes

Findings:

• Fundal pressure associated with:
  • Increased brachial plexus injury (RR 3.5)
  • Increased uterine rupture
  • NO improvement in delivery success

Impact: Fundal pressure recognized as contraindicated

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Exam Detail: Viva Question: "What is the evidence regarding routine induction of labor for suspected fetal macrosomia?"

Model Answer:

"The evidence does NOT support routine induction of labor for suspected macrosomia in the 4000-4500g range.

Several key studies and guidelines inform this:

ACOG Practice Bulletin 178 (2017) reviewed the evidence and concluded that:

• Ultrasound estimation of fetal weight has significant error margins (±15-20%)
• Induction of labor for suspected macrosomia (EFW 4000-4500g) in non-diabetic women does NOT reduce shoulder dystocia rates
• It DOES increase cesarean section rates without improving neonatal outcomes
• Therefore, routine induction is NOT recommended in this weight range

RCOG Green-Top Guideline 42 similarly does NOT recommend routine induction for macrosomia.

When might delivery intervention be considered?

• EFW ≥4500g (non-diabetic): CS may be discussed (ACOG uses 5000g threshold)
• EFW ≥4000g (diabetic): Earlier delivery (38-39 weeks) and consideration of CS, given asymmetric macrosomia and higher shoulder dystocia risk at lower weights
• Previous severe shoulder dystocia with poor outcome

The key limitation is that ultrasound EFW is imprecise. To prevent one case of shoulder dystocia through prophylactic CS based on EFW thresholds, approximately 2500-3700 cesarean sections would need to be performed, with associated maternal morbidity.

The fundamental principle is that shoulder dystocia is largely unpredictable (50% occur in non-macrosomic babies), so the most effective strategy is universal preparedness through training, rather than attempting prevention through delivery intervention based on estimated weight alone."

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11. Examination Focus

High-Yield Viva Topics

1. Immediate Recognition and Response

Q: "You are attending a delivery. The fetal head delivers, but with the next push, the head retracts tightly against the perineum and does not rotate. What has happened and what do you do immediately?"

A: "This is the turtle sign, pathognomonic for shoulder dystocia. The anterior shoulder has become impacted behind the pubic symphysis, creating a bony obstruction. I immediately:

1. Call for help – senior obstetrician, additional midwives, neonatologist, anaesthetist
2. Note the time (or assign scribe to document)
3. Do NOT apply fundal pressure or excessive traction
4. Initiate HELPERR algorithm starting with McRoberts manoeuvre"

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2. McRoberts Manoeuvre Mechanism

Q: "How does the McRoberts manoeuvre work?"

A: "McRoberts manoeuvre is hyperflexion of the maternal thighs onto the maternal abdomen. Biomechanically, it:

• Flattens the lumbar lordosis
• Rotates the pubic symphysis cephalad by approximately 8 degrees
• Flattens the sacral promontory, increasing the AP diameter of the pelvic inlet by 1-2cm
• Increases the pelvic inlet angle, aligning the axis of the pelvis with the direction of expulsive force These changes facilitate passage of the impacted anterior shoulder under the pubic arch. It resolves 40-50% of cases alone, and 90% when combined with suprapubic pressure."

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3. Fundal Pressure Contraindication

Q: "Why is fundal pressure contraindicated in shoulder dystocia?"

A: "Fundal pressure is absolutely contraindicated because it:

• Pushes the entire fetus downward
• Increases the impaction of the anterior shoulder behind the pubic symphysis (does NOT dislodge it)
• Dramatically increases risk of:
  • Brachial plexus injury (through reflex excessive traction by the operator)
  • Uterine rupture (particularly in scarred uteri)
  • Fetal death

Gross et al. demonstrated a 3.5-fold increase in brachial plexus injury with fundal pressure and no improvement in delivery success. The correct pressure is suprapubic pressure, applied downward and posteriorly from above the pubis, which adducts the shoulders and may dislodge the impacted shoulder."

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4. Internal Manoeuvres

Q: "Describe the Rubin II and Woods Screw manoeuvres."

A:

"Rubin II Manoeuvre: The objective is to adduct the shoulders to reduce the bisacromial diameter. I insert my hand into the vagina, locate the anterior shoulder (on the same side as the fetal back), and place my fingers on the posterior aspect of the anterior shoulder (the surface facing the fetal chest). I then push toward the fetal chest, adducting the shoulder. This reduces the shoulder-to-shoulder diameter and may dislodge the anterior shoulder from behind the pubis.

Woods Screw Manoeuvre: The objective is to rotate the fetus 180 degrees to bring the posterior shoulder anteriorly, like unscrewing a corkscrew. I insert my hand and locate the posterior shoulder. I place my fingers on the anterior aspect of the posterior shoulder (the surface facing away from the fetal chest) and push circumferentially to rotate the shoulder through a 180-degree arc anteriorly. As the posterior shoulder rotates to become the new anterior shoulder, it delivers under the pubic arch first, and the original impacted anterior shoulder (now posterior) delivers over the perineum.

Both manoeuvres are second-line, used if McRoberts + suprapubic pressure are unsuccessful after 30-60 seconds."

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5. Posterior Arm Delivery

Q: "When would you deliver the posterior arm, and how is it done?"

A: "Posterior arm delivery is attempted if internal rotational manoeuvres (Rubin/Woods) are unsuccessful. It is highly effective.

Technique: I insert my hand into the vagina along the fetal posterior shoulder and follow the arm down to the elbow. I flex the elbow, bringing the forearm across the fetal chest, and sweep the forearm and hand out through the vagina. With the posterior arm delivered, the bisacromial diameter is effectively reduced to a shoulder-to-chest diameter, allowing the fetus to rotate and the anterior shoulder to deliver easily.

Risk: There is a 5-10% risk of humerus or clavicle fracture during this manoeuvre. However, these fractures heal very well, and this risk is far preferable to fetal death or hypoxic brain injury from prolonged impaction. Parental counseling post-delivery should explain this."

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6. Time-Critical Nature

Q: "What is the significance of the head-to-body delivery interval in shoulder dystocia?"

A: "Once the head delivers but the body remains impacted, the umbilical cord is compressed between the fetal body and the maternal pelvis, interrupting fetal oxygenation. This creates a time-critical emergency:

• 5-6 minutes: Risk of hypoxic-ischaemic encephalopathy (HIE) begins to rise sharply
• > 10 minutes: High risk of severe HIE, permanent brain damage, or fetal death

This is why the HELPERR manoeuvres must be performed systematically but rapidly, without delay. Every manoeuvre should be attempted for approximately 30-60 seconds before moving to the next if unsuccessful. Documentation of timing by a scribe is important both for clinical management and medico-legal purposes."

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7. Brachial Plexus Injury

Q: "What is Erb's palsy and what is the prognosis?"

A: "Erb's palsy is a brachial plexus injury affecting the upper nerve roots C5-C6 (and sometimes C7). It occurs in approximately 10-15% of shoulder dystocia cases and results from lateral traction or lateral flexion of the fetal head/neck during delivery.

Clinical Features:

• Absent Moro reflex on affected side
• 'Waiter's Tip' posture: Shoulder adducted and internally rotated, elbow extended, forearm pronated, wrist flexed
• Absent biceps and brachioradialis reflexes
• Preserved hand grasp (C8-T1 intact)

Prognosis:

• 70-90% recover fully within 12 months
• 10-30% have persistent weakness
• 5-10% have permanent significant disability
• Early return of function (within 2 weeks) is a favorable prognostic sign

Management: Immediate neonatal and neurology assessment, physiotherapy to prevent contractures, and consideration of nerve repair/grafting if no recovery by 3-6 months.

Important point: Brachial plexus injury can occur even with appropriate manoeuvres, as the impaction itself creates traction forces. It is not always preventable, though avoiding fundal pressure and excessive traction reduces risk."

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8. Subsequent Pregnancy Counseling

Q: "A woman had shoulder dystocia in her previous pregnancy. How do you counsel her for the next pregnancy?"

A: "I would discuss the recurrence risk, which is approximately 10-15% in a subsequent vaginal delivery. This means 85-90% will NOT have a recurrence.

Options for next delivery:

Option 1: Supervised Trial of Vaginal Delivery

• Most women can attempt vaginal delivery
• Should be in hospital with senior staff immediately available
• Continuous fetal monitoring
• Team prepared for shoulder dystocia (HELPERR protocol ready)
• Relative contraindications: EFW ≥4500g (non-diabetic) or ≥4000g (diabetic), maternal diabetes, previous severe shoulder dystocia with poor neonatal outcome

Option 2: Elective Cesarean Section

• Eliminates risk of recurrent shoulder dystocia
• Carries surgical risks: bleeding, infection, VTE, impact on future pregnancies (placenta previa/accreta)
• Indications: Maternal preference after counseling, previous severe shoulder dystocia with adverse outcome, estimated fetal weight above thresholds

Key counseling points:

• Informed choice with balanced discussion of risks and benefits
• Ultrasound EFW has significant error margins
• If diabetes present, optimize glycemic control antenatally
• Birth plan documented and discussed with delivery team
• Opportunity for questions and psychological support if traumatic previous experience"

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9. Evidence: Induction for Macrosomia

Q: "Should you routinely induce labor for suspected fetal macrosomia?"

A: "No. Evidence from ACOG Practice Bulletin 178 and RCOG Green-Top Guideline 42 demonstrates that routine induction of labor for suspected macrosomia (EFW 4000-4500g) in non-diabetic women:

• Does NOT reduce shoulder dystocia rates
• Does NOT improve neonatal outcomes
• DOES increase cesarean section rates

Reasons:

• Ultrasound EFW has wide error margins (±15-20%)
• 50% of shoulder dystocia occurs in non-macrosomic babies
• To prevent one shoulder dystocia through prophylactic CS, ~2500-3700 cesareans would be needed

When intervention may be considered:

• EFW ≥4500g (non-diabetic): Discuss CS (ACOG uses 5000g)
• EFW ≥4000g (diabetic): Earlier delivery (38-39 weeks) and consideration of CS given asymmetric macrosomia

Most effective strategy: Universal preparedness through training, not selective intervention based on estimated weight."

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10. Simulation Training Evidence

Q: "What is the evidence for simulation training in shoulder dystocia?"

A: "Draycott et al. (2008) published landmark evidence on the PROMPT (PRactical Obstetric Multi-Professional Training) program. This before-and-after study demonstrated that regular multi-professional simulation drills in shoulder dystocia management:

• Reduced brachial plexus injury from 9.3 to 2.3 per 1000 births
• Reduced hypoxic-ischaemic encephalopathy rates
• Improved team communication and manoeuvre performance

Mechanism: Simulation ('drills') improves:

• Recognition speed (turtle sign)
• Correct manoeuvre sequencing (HELPERR)
• Team coordination and role allocation
• Avoidance of harmful actions (fundal pressure)

Recommendation: RCOG and ACOG recommend regular (every 6-12 months) multi-professional shoulder dystocia simulation training for all maternity staff. This is the most effective evidence-based intervention to improve outcomes, given that shoulder dystocia is largely unpredictable."

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OSCE Scenarios

Scenario 1: Breaking Bad News – Erb's Palsy

Setup: The baby has been delivered after shoulder dystocia and has Erb's palsy. Counsel the parents.

Expected Performance:

1. Introduce yourself, confirm parents' understanding of what happened
2. Explain Erb's palsy: "During the delivery, there was pressure on the nerves that control the arm, called the brachial plexus. This has caused temporary weakness in [baby's] arm."
3. Show understanding: "I know this is very distressing for you."
4. Explain prognosis: "The good news is that in 70-90% of cases, these injuries recover completely within the first year. We will closely monitor progress."
5. Explain management: "The pediatric team will examine [baby] today, and we will arrange physiotherapy to keep the arm moving and prevent stiffness. A specialist neurologist will follow up."
6. Invite questions
7. Document and arrange follow-up

Scenario 2: Counseling for Next Pregnancy

Setup: Woman presents in antenatal clinic. Previous delivery complicated by shoulder dystocia. Current pregnancy, EFW 3800g at 37 weeks. Discuss delivery options.

Expected Performance:

1. Explore previous experience and feelings about it
2. Explain recurrence risk (10-15%)
3. Discuss Option 1: Vaginal delivery (supervised, hospital, senior staff, preparedness)
4. Discuss Option 2: Elective CS (eliminates shoulder dystocia risk but has surgical risks)
5. Discuss current EFW (within normal range, ultrasound has error margins)
6. Explore her preferences
7. Make a plan together
8. Document and communicate plan to delivery team

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12. Patient and Layperson Explanation

What is Shoulder Dystocia?

Shoulder dystocia is a rare but serious emergency that can happen during childbirth. It occurs when the baby's head is born, but the shoulders become stuck inside the mother's pelvis and cannot deliver normally. We need to act very quickly to help deliver the rest of the baby safely.

Why Does It Happen?

During a normal delivery, after the baby's head comes out, the shoulders usually follow easily with the next push. In shoulder dystocia, the baby's front shoulder gets caught behind the mother's pelvic bone (called the pubic bone). This creates a blockage that gentle pulling cannot fix.

It is more common if:

• The baby is quite large (though it can happen with normal-sized babies too)
• The mother has diabetes (which can affect how the baby grows)
• It happened in a previous pregnancy

However, about half of all cases happen without any warning signs, in normal-sized babies to mothers without risk factors. This means doctors and midwives must always be prepared for it.

How Do You Know It's Happening?

After the baby's head delivers, instead of the body following quickly, the head pulls back tightly against the mother (this is called the "turtle sign" because it looks like a turtle pulling its head back into its shell). This is the sign that tells us there is a problem and we need to act immediately.

What Do You Do?

We follow a step-by-step emergency plan called HELPERR:

1. Call for Help: We immediately call for senior doctors, extra midwives, and the baby doctor (pediatrician) to come and help.

2. Create Space: We may need to make a small cut (episiotomy) to create more room to help.

3. Change the Mother's Position (McRoberts Manoeuvre): We help you bring your legs up and bend your knees onto your tummy. This opens up your pelvis and helps create space for the baby's shoulder to come free. This works in about half of cases.

4. Apply Gentle Pressure on Your Tummy: A helper presses gently just above your pubic bone (NOT on the top of your tummy – that would be dangerous). This helps move the baby's shoulder into a better position.

5. Internal Manoeuvres: If the above steps don't work, the doctor will reach inside and try to gently rotate the baby or move the baby's arm to help the shoulders pass through.

6. Try Different Positions: Sometimes we might help you move to your hands and knees, as this can change the shape of the pelvis and help the baby deliver.

In most cases (9 out of 10), the baby delivers successfully with the first two steps (changing leg position and gentle pressure).

What Must You NOT Do?

There is one thing that is very dangerous and must never be done: pushing on the top of your tummy (called fundal pressure). This would make the problem worse and could seriously harm you and the baby. We only ever press gently just above the pubic bone, not on the upper belly.

Could My Baby Be Hurt?

With quick and correct action, most babies are born safely with no long-term problems. However, there are some possible injuries:

• Arm Nerve Injury (Erb's Palsy): The baby's arm nerves can be stretched during delivery, causing temporary weakness in one arm. This happens in about 1 in 10 cases of shoulder dystocia. The good news is that 70-90% of these injuries heal completely within the first year. Your baby will see a specialist and have physiotherapy to help.

• Broken Collarbone or Arm Bone: Sometimes the baby's collarbone or arm bone can break during the maneuvers. This sounds scary, but babies' bones heal very quickly and well (usually within 2-3 weeks) and this is much better than the alternative of leaving the baby stuck.

• Breathing Problems: If the baby is stuck for too long (more than 5-6 minutes), the oxygen supply through the umbilical cord can be reduced. This is why we act so quickly. With fast action, serious breathing problems are very rare (less than 1-2%).

Could I Be Hurt?

You may have:

• More bleeding than usual after delivery
• More tearing that needs stitches
• Emotional distress from the emergency

We will carefully check and treat any physical injuries immediately. We will also talk to you afterward to explain what happened and answer your questions, as we know this can be a frightening experience.

What Happens Afterward?

After the delivery:

• The baby will be checked carefully by the pediatrician
• We will examine you and repair any tears
• We will talk to you and your partner to explain exactly what happened
• You will have a chance to ask any questions
• We will give you a written report
• You will have extra support and follow-up appointments to check how you and your baby are doing

What About Future Pregnancies?

If you have another baby in the future, there is about a 10-15% chance (roughly 1 in 8) that shoulder dystocia might happen again. However, this also means that about 85-90% of the time, it does NOT happen again.

When you become pregnant again, we will discuss your options with you:

• You can choose to have a normal vaginal delivery with extra precautions and senior staff present
• Or you can choose to have a planned cesarean section to avoid the risk of it happening again

We will support you in making the choice that is right for you.

Key Message

Shoulder dystocia is a serious emergency, but with quick recognition and the right actions, almost all babies are delivered safely. The medical team is trained to handle this, and we will do everything we can to keep you and your baby safe.

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13. References

Primary Sources

1. Royal College of Obstetricians and Gynaecologists (RCOG). Shoulder Dystocia (Green-top Guideline No. 42). 2012 (Updated 2017). https://www.rcog.org.uk/guidance/browse-all-guidance/green-top-guidelines/shoulder-dystocia-green-top-guideline-no-42/

2. Mehta SH, Bujold E, Blackwell SC. Shoulder Dystocia: Risk Factors, Predictability, and Preventability. Semin Perinatol. 2014;38(4):189-193. doi:10.1053/j.semperi.2014.04.007

3. Gherman RB. Shoulder Dystocia: An Evidence-Based Evaluation of the Obstetric Nightmare. Clin Obstet Gynecol. 2002;45(2):345-362. doi:10.1097/00003081-200206000-00007

4. Leung TY, Stuart O, Sahota DS, Suen SSH, Lau TK, Lao TT. Head-to-Body Delivery Interval in Shoulder Dystocia: Risk Factors and Neonatal Outcome. J Matern Fetal Neonatal Med. 2011;24(11):1304-1308. doi:10.3109/14767058.2011.556206

5. American College of Obstetricians and Gynecologists (ACOG). Shoulder Dystocia (Practice Bulletin No. 178). Obstet Gynecol. 2017;129(5):e123-e133. doi:10.1097/AOG.0000000000002043

6. Spong CY, Beall M, Rodrigues D, Ross MG. An Objective Definition of Shoulder Dystocia: Prolonged Head-to-Body Delivery Intervals and/or the Use of Ancillary Obstetric Maneuvers. Obstet Gynecol. 1995;86(3):433-436. doi:10.1016/0029-7844(95)00188-9

7. Ju H, Chadha Y, Donovan T, O'Rourke P. Fetal Macrosomia and Pregnancy Outcomes. Aust N Z J Obstet Gynaecol. 2009;49(5):504-509. doi:10.1111/j.1479-828X.2009.01052.x

8. Hedderson MM, Weiss NS, Sacks DA, et al. Pregnancy Weight Gain and Risk of Neonatal Complications: Macrosomia, Hypoglycemia, and Hyperbilirubinemia. Obstet Gynecol. 2006;108(5):1153-1161. doi:10.1097/01.AOG.0000242568.75785.68

9. Acker DB, Sachs BP, Friedman EA. Risk Factors for Shoulder Dystocia. Obstet Gynecol. 1985;66(6):762-768.

10. Gross SJ, Shime J, Farine D. Shoulder Dystocia: Predictors and Outcome. A Five-Year Review. Am J Obstet Gynecol. 1987;156(2):334-336. doi:10.1016/0002-9378(87)90278-8

11. Gherman RB, Tramont J, Muffley P, Goodwin TM. Analysis of McRoberts' Maneuver by X-ray Pelvimetry. Obstet Gynecol. 2000;95(1):43-47. doi:10.1016/s0029-7844(99)00434-x

12. Pedersen J. The Pregnant Diabetic and Her Newborn: Problems and Management. 2nd ed. Baltimore: Williams & Wilkins; 1977.

13. Ginsberg NA, Moisidis C. How to Predict Recurrent Shoulder Dystocia. Am J Obstet Gynecol. 2001;184(7):1427-1430. doi:10.1067/mob.2001.113127

14. Stotland NE, Caughey AB, Breed EM, Escobar GJ. Risk Factors and Obstetric Complications Associated with Macrosomia. Int J Gynaecol Obstet. 2004;87(3):220-226. doi:10.1016/j.ijgo.2004.08.010

15. Benedetti TJ, Gabbe SG. Shoulder Dystocia: A Complication of Fetal Macrosomia and Prolonged Second Stage of Labor with Midpelvic Delivery. Obstet Gynecol. 1978;52(5):526-529.

16. Athukorala C, Middleton P, Crowther CA. Intrapartum Interventions for Preventing Shoulder Dystocia. Cochrane Database Syst Rev. 2006;(4):CD005543. doi:10.1002/14651858.CD005543.pub2

17. ACOG Committee on Practice Bulletins—Obstetrics. ACOG Practice Bulletin No. 173: Fetal Macrosomia. Obstet Gynecol. 2016;128(5):e195-e209. doi:10.1097/AOG.0000000000001767

18. Garthus-Niegel S, von Soest T, Vollrath ME, Eberhard-Gran M. The Impact of Subjective Birth Experiences on Post-Traumatic Stress Symptoms: A Longitudinal Study. Arch Womens Ment Health. 2013;16(1):1-10. doi:10.1007/s00737-012-0301-3

19. Draycott TJ, Crofts JF, Ash JP, et al. Improving Neonatal Outcome Through Practical Shoulder Dystocia Training. Obstet Gynecol. 2008;112(1):14-20. doi:10.1097/AOG.0b013e31817bbc61

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Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances and be made in consultation with senior colleagues and appropriate specialists. In emergency situations, follow local protocols and guidelines. This content is designed to support clinical learning for postgraduate medical examinations (MRCOG, MRCP, MRCS) and should not replace clinical judgment or supersede local clinical governance.

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Document Information:

• Topic ID: obs-shoulder-dystocia
• Last Updated: 2025-01-06
• Evidence Level: High
• Citation Count: 19
• Word Count: ~11,500
• Target Audience: MRCOG candidates, Obstetrics trainees, Emergency Medicine, Midwifery
• Examination Focus: High-yield for MRCOG Part 2 (written SBAs), Part 3 (clinical assessment, structured discussion), OSCE stations

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