shoulder dystocia

Question 1

What are the causes of shoulder dystocia?

Answer 1

Passages
- congenital or acquired deformity
- narrow pelvic cavity
- previous pelvis trauma

Passenger
- malpresentation/malposition
- macrosomia
- CFMF

Power
- hyper/hypotonicity

Question 2

What is the pathophysiology of shoulder dystocia?

Answer 2

1- fetal shoulder remains in anterior-posterior position at pelvic inlet
2- anterior shoulder impacted behind symphysis pubis OR posterior shoulder obstructed by sacral promontory

Question 3

What are the maternal risk factors for shoulder dystocia?

Answer 3

• maternal short stature <150cm
• advanced maternal age >35y
• high maternal birth weight
• BMI > 35
• grand-multiparity > 5 deliveries
• diabetes mellitus
• history of previous shoulder dystocia

Question 4

What are the fetal risk factors for shoulder dystocia?

Answer 4

• previous delivery of large to date
• EFW > 4kg
• post-dated
• fetal male gender
• broad fetal shoulder (>14cm = EFW > 4.2)

Question 5

What are the intrapartum risk factors for shoulder dystocia?

Answer 5

• prolonged active phase of labour
• unexplained prolonged 2nd stage
• induction of labour with increased use of oxytocin
• operative vaginal delivery
• no external rotation of fetal head

Question 6

What are the complications of shoulder dystocia?

Answer 6

MATERNAL
- traumatic or atonic PPH
- female genital fistula
- symphyseal separation or diathesis +- femoral neuropathy
- uterine rupture
- birth canal tears
- post partum depression

FETAL
- brachial plexus injury
- fetal hypoxia
- fracture of clavicle
- fracture of humerus
- perinatal/neonatal death

Question 7

What are the diagnostic signs for shoulder dystocia?

Answer 7

• difficult delivery of fetal face & chin
• turtle-neck sign
• failure of restitution of the fetal head
• failure of the shoulder to descend if a gentle axial traction fails to deliver anterior shoulder

Question 8

How should shoulder dystocia be managed after diagnosis?

Answer 8

OB has 7 minutes to deliver
1- call for help
2- mother should NOT push down during attempts to reposition fetus
3- drain out bladder if distended
4- AVOID excessive neck rotation, head & neck traction, & fundal pressure
5- patient should be positioned with her buttocks flush with the edge of bed
6- generous episiotomy

Question 9

What are the maneuvers that could be used do aid in delivery complicated by shoulder dystocia?

Answer 9

1- McRobert’s -> woman’s legs are flexed over her abdomen

2- Rubin’s I -> pressure Supra-pubically directed from back to face

3- Rubin’s II -> 2 fingers behind posterior shoulder & rotate anteriorly

4- Wood’s screw -> 2 fingers on anterior & 2 fingers on posterior shoulders

5- Barnum -> pressure on antecubital fossa to flex elbow & allow forearm to be grasped

6- Gaskin all-four -> mother on hands & knees

7- Zavanelli -> replace fetal head inside & C section

8- Cleidotomy
9- symphysiotomy