Welcome back to another episode. Today, I’m going to walk you through how to identify and manage shoulder dystocia.

Before we dive in, I want to invite you to a live one-hour training I’m hosting over the next two weeks called The Intern’s Guide to Managing Labor: Induction and Augmentation. We’ll cover how to counsel patients, use the Bishop score, review all the major induction methods, and wrap up with a Q&A. If you’re an incoming OB/GYN intern or a student hoping to match into the specialty, this is a great way to get a head start! Click here to register!

What Is Shoulder Dystocia?

Shoulder dystocia is defined as the failure to deliver the fetal shoulder(s) with gentle downward traction on the fetal head, requiring additional obstetric maneuvers to achieve delivery. It typically involves the anterior shoulder being stuck behind the pubic symphysis, but it can also be due to the posterior shoulder lodging behind the sacral promontory.

The incidence is approximately 0.2–3%, and the recurrence rate ranges from 1–16%, with most studies reporting at least 10%. Keep in mind, many patients with prior shoulder dystocia elect to deliver via cesarean in subsequent pregnancies, so this recurrence rate may be underestimated.

Risk Factors

While maternal diabetes and suspected macrosomia are common risk factors, most cases occur in non-diabetic patients delivering normal-weight babies. In other words, shoulder dystocia is generally unpredictable and unpreventable.

That said, ACOG supports offering elective cesarean delivery to:

Diabetic patients with an estimated fetal weight ≥4500 g
Non-diabetic patients with an estimated fetal weight ≥5000 g

These thresholds may show up on exams, so they’re worth remembering.

Diagnosing Shoulder Dystocia

Shoulder dystocia is diagnosed when the shoulders fail to deliver after the fetal head restitutes (i.e., rotates from occiput anterior to a right or left-facing position) and gentle downward traction on the head fails.

Side note for interns: you're unlikely to be the one diagnosing it during delivery—a senior resident or attending will typically step in to assess before making the call.

First Steps When Shoulder Dystocia Is Identified

Call it out: Announce to the room that a shoulder dystocia is present and ask someone to start a timer.
Tell the patient to stop pushing: You need space to work.

The 7 Primary Maneuvers

McRoberts: Two assistants hyperflex the patient’s thighs back against their abdomen. This flattens lumbar lordosis and tilts the pubic symphysis cephalad.
Suprapubic Pressure: Another assistant applies downward and lateral pressure to the anterior shoulder. Be specific—tell them which way to push based on which direction the head restituted.
Posterior Arm Delivery: Insert your hand far into the vagina to find the posterior arm, flex the elbow, and sweep it across the chest and out of the vagina. If space is tight, consider an episiotomy.
Rubin Maneuver: Insert a hand to the posterior shoulder's back surface and rotate it inward toward the fetal face.
Woods Screw Maneuver: Instead of the back, apply pressure to the anterior clavicle of the posterior arm and rotate the shoulder away from the face.
Axillary Sling: Thread a soft catheter under the posterior arm's axilla, create a sling, and apply moderate traction to deliver the arm.
Gaskin Maneuver: Turn the patient onto all fours and apply downward or upward traction. Only feasible if the patient does not have an epidural.

What If None of Those Work?

Repeat all the above maneuvers.

If they repeatedly fail, move to last-resort interventions:

Intentional Clavicle Fracture: Decreases the bisacromial diameter.
Zavanelli Maneuver: Push the fetal head back into the vagina and proceed to emergency cesarean delivery. High morbidity and mortality.
Abdominal Rescue: Perform a laparotomy and hysterotomy, manually dislodge the shoulder from above, and assist vaginal delivery from below.

Summary

Shoulder dystocia = failure to deliver shoulder(s) with gentle traction.
Risk factors include diabetes and macrosomia, but most cases are unpredictable.
Initial steps: call it, start the timer, and stop maternal pushing.
7 maneuvers: McRoberts, suprapubic pressure, posterior arm delivery, Rubin, Woods Screw, axillary sling, and Gaskin.
Last resorts: clavicle fracture, Zavanelli maneuver, abdominal rescue.