Shoulder Dystocia Flashcards
Definition of Shoulder Dystocia?
Shoulder dystocia refers to the difficulty in delivering the fetal shoulders, after delivery of the fetal head. it constitutes the need for additional manoeuvres and results in a time delay between head and shoulder delivery.
Describe the pathophysiology of shoulder dystocia?
- The fetal bisacromial diameter (the distance between the shoulder) is too wide for the anteroom-posterior diameter of the maternal pelvis.
- The anterior fetal shoulders are generally wedged under the maternal symphysis pubis
- Less commonly the posterior shoulder is impacted on the maternal sacral promontory.
- Its a bony rather than soft tissue issue.
- Requires the presentation to be cephalic
Name the 4 parameters of diagnosis of shoulder dystocia?
- The head is born but remains tightly applied to the vulva
- There is difficulty with the birth of the face and the chin
- The turtle sign (the chin retracts into the perineum)
- The anterior shoulder does not birth with normal downward traction
What at the fetal complications of shoulder dystocia which are classified as bad?
Bone fractures - of the clavicle and the humerus .
- It can be accidental or intentional
- Prognosis is good
- Transient brachial plexus palsy
What are the fetal complications of shoulder dystocia which are classified as very bad?
- Permanent brachial plexus palsy
What is a fetal complication of shoulder dystocia which is considered extremely bad?
- Asphyxia/ hypoxic ischaemic encephalopathy
Maternal complications of shoulder dystocia? Name 4
Minimal compared to fetal, sometimes justified to protect the fetus.
- Trauma to the birth canal (incl. anal spincter injury)
- Haemorrhage
- Uterine rupture (rare)
- Psychology trauma
Anterpartum shoulder dystocia risk factors?
- prior shoulder dystocia
- fetal macrosomia (especially >4500 g)
- Maternal Diabetes mellitus
- Male fetal gender
- Maternal obesity
Intrapartum shoulder dystocia risk factors?
- Prolonged labour (first and/or second stage)
- Induction of labour
- Augmented labour
- Instrument delivery
Management Principles of Shoulder Dystocia. Name three things to avoid or never to do!?
- Never rotate fetal head
- avoid fundal pressure
- Avoid excessive traction at all times
Name the three broad principles of management of fetal dystocia? think anatomically
- Increase the functional size of the bony pelvis
- Decrease the bisacromial diameter of the fetus
- change the relationship of the bisacromial diameter within the bony pelvis by rotating the fetus into the wider oblique diameter
Management algorithm of shoulder dystocia?
H - Call for help: E.g. senior obstetric, midwife, paediatric, instruct patient to stop pushing, move patient flat on back to initiate manoeuvres
E - Evaluate episiotomy, aids in the access of internal manoeuvres
L - Legs (McRoberts Position):
- Abduct and hyperflex thighs onto maternal abdomen bilaterally, thereby opening maternal pelxis
- Gentle downward traction
P - Pressure (suprapubic)
- Also known as rubin 1
- Aims to reduce fetal bisacromial diameter and rotate to oblique plane
- Constant or rocking motion
- Anterior shoulder should slip out from the under the pubic symphasis
E - Enter rotational manoeuvres
- Rubin II
- Rubin II + Woods corkscrew manoeuvre
- Reverse woods corkscrew manoeuvre
R- Remove the posterior arm (Barnum)
- Apply antecubital fossa pressure to flex the elbow in front of the body, or grasp posterior hand to sweep the arm across the chest and deliver the arm
- Rotate the fetus into oblique position and deliver
R- Roll the patient onto all fours (gasking)
- Act of rolling may dislodge shoulder
- open pelvis in AP plane
- Apply gentle downward traction to disimpact posterior shoulder from sacral promontory
In terms of shoulder dystocia management what are the manoeuvres of last resort?
- Deliberate cleidotomy: Fracture of fetal clavicle pulling it outward
- Zanelli Manoevre: fetal head is pushed back inside vagina/ uterus and held until C section
- Hysterotomy/ transabdominal rotation
- If fetal head cannot be replaced, uterus can be incised and internal attempts made at rotating fetus
- Symphysiotomy: extremely morbid, resorved for situation were recourse to C section is not available
Discuss shoulder dystocia prevention?
Anticipatory and prophylactic manoeuvres: E.g. reduce maternal obesity, difficult forceps delivery
- C section is macrosomia (low yield)
- Early induction in macrosomia not shown to decrease shoulder dystocia
