Mx - Shoulder Dystocia

Question 1

Shoulder dystocia occurs when

Answer 1

there is a size discrepancy between fetal shoulders and the pelvic inlet, and the anterior shoulder becomes wedge under the maternal pubic symphysis

Question 2

Around half of the cases are completely unexpected in absence of risk factors, however risk factors are

Answer 2

Maternal -
GDM
obesity
prolonged labour
instrumental delivery
previous shoulder dystocia

Fetal -
macrosomia
post-dates
anomalies

Question 3

Shoulder dystocia is an emergency requiring delivery within a few minutes because

Answer 3

the umbilical cord is compressed between the fetal body and maternal pelvis, causing fetal pH to fall rapidly by 0.04 units per minute resulting in asphyxia and death

Question 4

How is shoulder dystocia managed?

Answer 4

1) Call for help from MDT - obstetrics, midwifery, paediatric and anaesthetic staff
2) Position woman - dorsal lithotomy and perform episiotomy to assist manoeuvres and apply downward traction to fetal head
3) McRoberts position - sharp flexion of thighs against abdomen with suprapubic pressure in order to disimpact shoulder from symphysis pubis
4) Wood’s corkscrew manouvre to abduct posterior shoulder and deliver the posterior arm
Most cases will be resolved within 4 minutes using these manoeuvres

Question 5

What are risks to fetus of delivery with shoulder dystocia?

Answer 5

fractured humerus or clavicle

Brachial plexus injury - resulting in permanent Erb’s palsy in <10% cases