Lecture Notes: Diagnosis and Management of Shoulder Dystocia

Introduction

• Lecturer: Julia Boucher, 4th-year medical student, University of Ottawa
• Topic: Shoulder dystocia in vaginal delivery
• Definition: An obstetrical emergency where additional maneuvers are required after delivery of the fetal head to deliver the shoulders
• Occurrence: ~1% of births

Causes of Shoulder Dystocia

• Anterior shoulder impaction: Common, occurs at maternal pubic symphysis
• Posterior shoulder impaction: Less common, occurs at maternal sacral promontory

Risk Factors

• Maternal diabetes
• Suspected macrosomia
• Gestational age >42 weeks
• Previous shoulder dystocia
• Operative delivery
• Note: >50% of cases are unpredictable, necessitating preparedness at every delivery

Diagnosis

• Clinical diagnosis
• Indicated when gentle, downward traction of the fetal head fails to deliver the anterior shoulder
• Early diagnosis is crucial to prevent fetal asphyxia from umbilical cord compression

Management

• Goal: Deliver the infant promptly without trauma
• Acronym for management: ALARMER

ALARMER Steps

1. A - Ask for Help
   • Pull alarm or call for additional staff
2. L - Legs (McRoberts Maneuver)
   • Hyperflex patient's legs, thighs against abdomen
   • Rotates pubis symphysis, flattens sacrum
   • Relieves obstruction in ~42% of cases
3. A - Apply Suprapubic Pressure/Anterior Shoulder Disimpaction
   • Use palm or fist to apply pressure, adducts/rotates shoulders
   • Rubin Maneuver: Hand in vagina, rotate posterior shoulder anteriorly
4. R - Release Posterior Shoulder
   • Hand in vagina, flex elbow, grasp forearm, pull out
   • Deliver fetal arm or shoulder if possible
5. M - Maneuver of Woods (Screw Maneuver)
   • Rotate fetus by applying pressure on posterior shoulder's clavicle
6. E - Episiotomy
   • Surgical cut to enlarge opening, better access to posterior arm
7. R - Roll onto All Fours
   • Use gravity to facilitate delivery

Last Resort Methods

• Increased risk of morbidity
  • Fetal clavicle fracture
  • Zavinelli maneuver (return fetal head, attempt cesarean)
  • Symphysiotomy (separation of maternal pubic bones)

Case Study: Sarah

• Patient: Sarah, 28-year-old, G1, 40 weeks, normal pregnancy
• Situation: Experienced turtle sign
• Action:
  • Used ALARMER steps
  • Combination of McRoberts and suprapubic pressure resolved dystocia
  • Successful delivery

Conclusion

• Shoulder dystocia requires prompt diagnosis to manage effectively
• ALARMER acronym provides structured management approach
• Key points of management include:
  • A: Ask for help
  • L: Legs (McRoberts)
  • A: Apply suprapubic pressure
  • R: Release posterior arm
  • M: Maneuver of Woods
  • E: Consider episiotomy
  • R: Roll onto all fours

Final Remarks

• Preparedness for shoulder dystocia is essential in every delivery
• Understanding and applying ALARMER acronym can aid in effective management