7.1 Shoulder Dystocia: Recognition & the HELPERR Protocol

Quick Summary: Shoulder dystocia is a time-critical emergency in which bone is impacted against bone, and it is resolved by an algorithm rather than by force. This section covers the biomechanics, the normoxic window, the turtle sign, and the full HELPERR sequence — including the one maneuver that is absolutely prohibited. Its complications, cord prolapse, and intraamniotic infection are covered in the next section.

---

Shoulder Dystocia: Definition, Biomechanics & Risk Factors

Shoulder dystocia is defined as a delivery that requires additional obstetric maneuvers beyond gentle downward axial traction to release the fetal shoulders after the head has delivered, or when the head-to-body delivery interval exceeds 60 seconds.

Pathophysiological Biomechanics

In normal cephalic delivery, the fetal shoulders enter the pelvic inlet in an oblique or transverse diameter. As the head extends and emerges over the perineum, the anterior shoulder rotates under the pubic symphysis. In shoulder dystocia, the anterior shoulder fails to rotate into the oblique diameter, remaining in the anteroposterior diameter and becoming mechanically impacted behind the bony maternal symphysis pubis (or rarely, the posterior shoulder becomes lodged behind the sacral promontory).

The Normoxic Window & Asphyxia Timeline

Following delivery of the head, the fetal chest remains compressed within the maternal pelvic canal, preventing respiratory expansion. Concurrently, compression of the umbilical cord between the fetal body and the maternal bony pelvis, combined with severe uterine contraction, drastically diminishes or halts fetoplacental gas exchange:

• A normoxic window of approximately 4 to 5 minutes exists before progressive fetal hypoxemia produces significant metabolic acidemia.
• Head-to-body delivery intervals > 7 minutes are strongly associated with irreversible hypoxic-ischemic encephalopathy (HIE), permanent neurological injury, and neonatal death.

Clinical Recognition: The "Turtle Sign"

• The fetal head crowns and delivers sluggishly over the perineum, but the chin tightly retracts and recoils backward against the maternal vulva and perineum ("turtle sign").
• Restitution fails to occur spontaneously, and gentle downward axial traction fails to deliver the anterior shoulder.

Risk Factors & Clinical Reality

• Maternal Risk Factors: Pre-gestational or gestational diabetes mellitus (insulin-dependent GDM alters fetal fat deposition, preferentially increasing shoulder circumference and chest-to-head ratio), maternal obesity (BMI ≥ 30), excessive gestational weight gain, postterm pregnancy (≥ 41 weeks), and short maternal stature.
• Labor Risk Factors: Prolonged second stage of labor, prolonged first stage, precipitous second stage, and operative vaginal delivery (forceps or vacuum extractor from the midpelvis).
• Prior Shoulder Dystocia: Carries a recurrence risk of 10% to 15%.
• Fetal Macrosomia: Estimated fetal weight > 4,500 g in non-diabetic women or > 4,000 g in diabetic women significantly elevates risk. ACOG recommends discussing elective cesarean delivery when EFW exceeds 5,000 g in non-diabetic women or 4,500 g in diabetic women.

Critical Clinical Reality: Over 50% of shoulder dystocia cases occur in infants weighing < 4,000 g born to women without identifiable risk factors. Therefore, antenatal risk factors possess low predictive value, and the CNM must be prepared to manage shoulder dystocia at every vaginal delivery.

---

The HELPERR Protocol: Algorithmic Stepwise Execution

The American Academy of Family Physicians (AAFP) Advanced Life Support in Obstetrics (ALSO) HELPERR mnemonic structures the emergency response into a logical clinical sequence:

1. H — Call for Help

• Announce the emergency clearly: "Shoulder dystocia, activate emergency protocol."
• Mobilize essential personnel: an obstetrician/surgical backup, pediatric resuscitation team (neonatologist/NNP), labor nurses, anesthesia personnel, and a designated recorder/timekeeper.
• Instruct the timekeeper to call out elapsed time every 30 to 60 seconds and record every maneuver performed.

2. E — Evaluate for Episiotomy

• Crucial Concept: Shoulder dystocia is a bony obstruction (bone impacted against bone), not a soft-tissue obstruction. An episiotomy does NOT release the bony impaction of the anterior shoulder.
• An episiotomy (procto-episiotomy or mediolateral) should be considered only if the clinician requires additional vaginal room to insert the hand for internal rotational maneuvers or posterior arm extraction.

3. L — Legs: The McRoberts Maneuver

• Hyperflex and abduct the mother's thighs tightly against her abdomen, while keeping the knees slightly apart. This requires two assistants holding the legs.
• Biomechanics: McRoberts maneuver straightens the maternal lumbosacral angle, flattens the sacral promontory, and rotates the pubic symphysis cephalad by approximately 1 cm, while directing the pelvic inlet perpendicular to the expulsive force. This simple positional change enlarges the functional anteroposterior pelvic diameter.
• Success: McRoberts maneuver, especially when combined with suprapubic pressure, resolves 40% to 50% of all shoulder dystocias.

4. P — Suprapubic Pressure (Rubin I Maneuver)

• An assistant places the heel of one or both hands directly over the maternal suprapubic bone, applying firm, continuous or rocking pressure downward and laterally against the posterior aspect of the anterior fetal shoulder (in the direction of the fetal chest).
• Biomechanics: This adducts the fetal shoulder girdle (collapsing the biacromial diameter) and pushes the anterior shoulder downward under the pubic arch into the oblique diameter of the pelvis.

ABSOLUTE CONTRAINDICATION — FUNDAL PRESSURE IS STRICTLY PROHIBITED: Applying fundal pressure during a shoulder dystocia is a lethal error. Fundal pressure wedges the impacted anterior shoulder further against the superior aspect of the pubic symphysis, drastically amplifies traction on the brachial plexus, precipitates complete nerve root avulsion, causes uterine rupture, and induces fetal intracranial hemorrhage.

5. E — Enter Maneuvers (Internal Rotational Maneuvers)

If McRoberts and suprapubic pressure fail, the clinician introduces a sterile gloved hand into the posterior vagina to manipulate the fetal shoulders into an oblique pelvic diameter:

• Rubin II Maneuver: The clinician inserts two fingers into the vagina behind the posterior aspect of the anterior fetal shoulder and pushes the shoulder toward the fetal chest (adduction), rotating it obliquely.
• Woods Screw Maneuver: While maintaining pressure on the posterior aspect of the anterior shoulder, the clinician inserts two fingers of the opposite hand on the anterior aspect of the posterior shoulder and applies torque in the same direction, turning the fetus 180 degrees like a screw to spin the posterior shoulder anteriorly under the pubic bone.
• Reverse Woods Screw Maneuver: If Woods screw fails, the fingers are placed on the posterior aspect of the posterior shoulder, rotating the fetus in the opposite direction.

6. R — Remove the Posterior Arm

• The clinician follows the posterior fetal humerus deep into the sacral hollow to the antecubital fossa.
• Pressure is applied in the antecubital fossa to flex the fetal elbow, bringing the forearm across the fetal chest.
• The clinician grasps the fetal wrist or hand and sweeps the forearm and hand out through the vulva, delivering the entire posterior arm.
• Biomechanics: Delivering the posterior arm instantly reduces the presenting shoulder diameter from the biacromial diameter (approximately 12 cm) to the axillo-acromial diameter (approximately 9.5 cm), freeing up 2 to 3 cm of pelvic space and almost always resulting in immediate delivery of the remainder of the fetus.

7. R — Roll onto All-Fours: The Gaskin Maneuver

• The laboring woman rolls over onto her hands and knees (all-fours position).
• Biomechanics: This position alters maternal pelvic geometry, widens the true conjugate diameter, and allows gravity to assist in dislodging the posterior shoulder from the sacral hollow. The clinician applies gentle downward traction on the posterior shoulder (now anterior in space) over the perineum.

Tertiary / Rescue Maneuvers of Last Resort

• Deliberate Clavicular Fracture: Upward and outward digital pressure against the mid-portion of the anterior clavicle, pulling away from underlying subclavian vessels and pleura.
• Zavanelli Maneuver (Cephalic Replacement): The fetal head is rotated back into the direct occiput anterior position, flexed, and gently pushed back into the vagina up into the uterine cavity, followed by immediate emergency cesarean delivery.
• Abdominal Rescue / Symphysiotomy: Surgical division of the fibrous cartilage of the pubic symphysis or hysterotomy-assisted shoulder extraction.

---