Shoulder dystocia Flashcards
Define shoulder dystocia.
A complication of vaginal cephalic delivery.
It entails the inability to deliver the body of the fetus using gentle traction, the head having already been delivered.
It usually occurs due to impaction of the anterior fetal shoulder on the maternal pubic symphysis.
Shoulder dystocia is a cause of both maternal and fetal morbidity.
What is the incidence of shoulder dystocia?
The incidence is around one in 150 vaginal births.
What are the risk factors for shoulder dystocia?
Maternal:
- diabetes mellitus
- high maternal BMI
Fetal:
- macrosomia (hence association with maternal diabetes mellitus)
Labour/uterine/placental:
- prolonged labour
- Prolonged first stage of labour
- Secondary arrest: no change in cervical dilation over time.
- Prolonged second stage of labour
- Oxytocin augmentation
- Assisted vaginal delivery
What is the management of shoulder dystocia?
Emergency buzzer + call for senior help
- McRoberts
- Episiotomy
- Suprapubic pressure
- Woodscrew’s manoeuvre
- Reverse Woodscrew’s
- Delivery of posterior arm
- All fours + repeat
- Cleidotomy / symphysiotomy / Zavenelli
What is McRobert’s maneouvre?
Hyperflex maternal hips to widen the pelvic outlet. This alone has a success rate of about 90% which is even higher when combined with suprapubic pressure.
What is the corkscrew maneouvre?
Internal rotation - simultaneously applying pressure in front of one shoulder and behind the other. The aim is to rotate the baby 180 degrees.
Does episiotomy decrease the risk of brachial plexus injury in this case?
An episiotomy can allow more space to facilitate internal vaginal manoeuvres but will not relieve the bony obstruction of the shoulder. The use of an episiotomy will not decrease the risk of brachial plexus injury.
NB: always prevent downward traction of the head as this increases risk of brachial plexus injury.
What is the post-delivery management in shoulder dystocia?
Active management of the third stage of labour - due to increased risk of PPH
Provide support and debrief the following delivery - can be traumatic for mother and partner
A rectal examination - to exclude a third- or fourth-degree tear
Paediatric review
What are the complications of shoulder dystocia?
Maternal complications:
- Third- or fourth-degree tears
- PPH
- Trauma/PTSD
Foetal complications:
- Brachial plexus injury (BPI)
- Fractures: humerus or clavicle
- Hypoxic brain injury.
What is the most common type of BPI?
Erb’s palsy (“waiter’s tip”) - it is usually temporary, and movement will return within hours or days. Permanent damage occurs in 10%
Why can hypoxic brain injury occur in shoulder dystocia?
The shoulder compression may cause the umbilical cord to become compressed between the baby’s body and the mother’s pelvis or the baby’s neck may be compressed at an angle that limits blood flow. Interruption of the oxygen supply may cause hypoxic brain injury potentially resulting in permanent functional change
