Shoulder dystocia

Question 1

Shoulder dystocia definition

Answer 1

A vaginal cephalic delivery that required additional obstetric manoeuvres to deliver the fetus after the head is delivered and gentle traction has failed
(RCOG 2012)

Question 2

How does shoulder dystocia occur?

Answer 2

Either the anterior, or less commonly the posterior, fetal shoulder impacts on the maternal symphysis, or sacral promontory respectively
(RCOG 2012)

Question 3

What diameter are the fetal shoulders in a shoulder dystocia?

Answer 3

In normal labour, the fetal shoulders enter the pelvic brim in the oblique or transverse diameter. In shoulder dystocia there is an arrest of the normal mechanism of labour as the shoulders attempt to enter the pelvis in the anteroposterior diameter of the pelvic brim
(Mayes 2012)

Question 4

Incidence of shoulder dystocia

Answer 4

There is a wide variation in the reported incidence of shoulder dystcoia. Ranges from 0.1% to 3.0%
Prompt (2017)

Question 5

Incidence of brachial plexus injury

Answer 5

2.3-16% of shoulder dystocia’s

RCOG 2012

Question 6

What percentage of shoulder dystocia’s occur with infants who weigh less than 4000g?

Answer 6

48%, therefore over half of shoulder dystocia’s occur in babies over 4000g
(RCOG 2012)

Question 7

Risk factors associated with shoulder dystocia

Answer 7

Previous shoulder dystocia
Macrosomia >4.5kg
Diabetes 
Maternal BMI >30
IOL
Prolonged first stage 
Secondary arrest
Prolonged second stage
Oxytocin augmentation
Assisted vaginal delivery 
(RCOG 2012)

Question 8

Reducing risk of shoulder dystocia for those with risk factors

Answer 8

Horvath et al (2012) did a meta analysis supporting IOL to reduce to risk of shoulder dystocia in maternal diabetes and suspected macrosomia.
The montgomery ruling (2015) is where a baby was brain damaged following shoulder dystocia. Pay out won despite being managed correctly as she wasn’t offered an IOL despite large baby identified and having gestational diabetes.

Question 9

Risk to mum

Answer 9

`PPH
Third and fourth degree tears 
Uterine rupture 
Psychological distress 
(Prompt 2017)

Question 10

Risk baby

Answer 10

Stillbirth
Hypoxia
Brachial plexus injury
Fractures (humeral and clavicular 
(Prompt 2017)

Question 11

Signs of shoulder dystocia

Answer 11

1. Difficulty with the delivery of the face and chin
2. The head remaining tightly applied to the vulva or even retracting (turtle neck sign)
3. Failure of restitution of the fetal head
4. Failure of the shoulders to descend
   (RCOG 2012)

Question 12

Time limits for the management of shoulder dystocia

Answer 12

No conclusive data but appears to be a very low rate of hypoxia ischemic injury upto five minutes
CESDI reported that 47% of babies died within 5 minutes of the head being delivered; but a high proportion already had a pathological CTG
(RCOG 2012)

Question 13

What rate does the fetal Ph drop?

Answer 13

0.04 a minute. Within 7 minutes the pH will have decreased by 0.28

Question 14

How to manage a shoulder dystocia?

Answer 14

1. CALL FOR HELP IMMEDIATELY
2. Lay flat and stop maternal pushing
3. Clearly state when people come into the room - ‘this is a shoulder dystocia’
4. McRoberts
5. Suprapubic pressure
6. Consider episiotomy if will make internal manoeuvres easier, but not always necessary
7. Internal manoeuvres - deliver posterior arm + internal rotational manoeuvres
8. All fours or repeat the above again
   (RCOG 2012)

Question 15

Why discourage maternal pushing?

Answer 15

May exacerbate impaction of shoulder

RCOG 2012

Question 16

McRoberts’ Position

Answer 16

The first choice of manoeuvre as has proven to be safe and effective. Requires the mother to lie flat on her back, then she is assisted into an exaggerated knee position. Once the mother has adopted this position, the midwife should be able to proceed with a normal delivery of the shoulders
(Mayes 2012)

Question 17

How does McRoberts’ position work?

Answer 17

Straighten the lumbosacral angle, roatate the maternal pelvis towards the mother’s head and increases the relative anterior posterior diameter of the pelvis. If in lithotomy position, need to be removed from her supports
(RCOG 2012)

Question 18

Success rate of McRoberts’ manoeuvre

Answer 18

As high a 90%, with a low rate of complications and is non invasive (RCOG 2012)

Question 19

Who to call for help in an obstetric?

Answer 19

• Senior Midwife
• Additional maternity staff
• Experienced obstetrician
• Neonatal team
  (Prompt 2017)

Question 20

Suprapubic pressure

Answer 20

Used if McRoberts’ if unsuccessful. Has a 50% success rate. (RCOG 2012)

Is intended to adduct and then displace the anterior shoulder away from the symphysis pubis and so allow it to enter the pelvis in the oblique diameter. Pressure is applied using the hand against the baby’s back in the direction that the baby is facing. (Mayes 2012)
Only routine traction should be applied to the fetal head when assessing whether the manoeuvre has been successful (RCOG 2012)

Question 21

Suprapubic pressure - rocking or continuous pressure?

Answer 21

No clear difference in the efficacy

RCOG 2012

Question 22

Traction applied during shoulder dystocia

Answer 22

The same degree of traction is applied as during normal birth, and in an axial direction
(Prompt 2017)

Question 23

Episiotomy???

Answer 23

Shoulder dystocia is a bony dystocia and as such is not greatly affected by soft tissue. An episiotomy may prevent injury to the mother’s pelvic floor and perineum during any direct manipulation of the fetus and/or accommodate the midwife’s or obstetrician’s hand whilst undertaking internal manoeuvres
(Mayes 2012)

Question 24

Internal manoeuvres

Answer 24

Should be used if McRoberts’ or suprapubic pressure fails. When gaining access to the vagina for internal manoeuvres enter into the sacral hollow (posteriorly) as that is the most spacious part of the pelvis. The whole hand should be entered posteriorly to perform internal rotation or delivery of the posterior arm. The women should be brought to the end of the bed to make access to the vagina easier

Question 25

Internal rotational manoeuvres

Answer 25

Most easily achieved by pressing on the anterior aspect or posterior aspect of the posterior shoulder. Pressure on the posterior aspect of the posterior shoulder has the added benefit of reducing the shoulder diameter by adducting the shoulders. Rotation should move the shoulders into the wider oblique diameter of the maternal pelvis, resolving the shoulder dystocia. Don’t need to rotate shoulder more than 20-30 degrees
(Prompt 2017)

Question 26

Delivering the posterior arm

Answer 26

Reduces the diameter of the fetal shoulders by the width of the arm. The fetal wrist should be grasped and the posterior arm should be gently withdrawn from the vagina in a straight line. Delivery of the posterior arm is associated with humeral fractures (reported incidence between 2-12%) but neonatal trauma may be a reflection of the refractory nature of the case, rather than the procedure
(RCOG 2012)

Question 27

What is the preferable internal manoeuvre?

Answer 27

No evidence suggesting one other another, thus decision should be based on training, clinical experience and the prevailing circumstances
(RCOG 2012)

Question 28

All fours position

Answer 28

Described as having a 83% success rate. Positioning the women in a flexed all-fours position with thighs against the abdomen has similar effect on the maternal pelvis as McRoberts’. Can be preferable for a slim, mobile women with a lone midwifery birth attendant. However hard with regional analgesia.
(Prompt 2017)

Question 29

Possible third line manoeuvres

Answer 29

Cleidotomy - surgical division of the clavicle or bending with a finger
Symphysiotomy - separation of the symphysis pubis to enlarge the pelvis. High incidence of serious maternal morbidity and poor neonatal outcome
Zavanelli - vaginal replacement of the head and then delivery by caesarean section. Success rates vary and maternal safety unknown
(RCOG 2012)

Question 30

After the delivery of the baby

Answer 30

Potential for PPH (11%) + 3rd and 4th (3.8%)
Examine baby for injury by neonatal clinician
DEBRIEF PARENTS!!!