1. Shoulder Dystocia Review July 24, 2014
Marie-Claude Laplante
Paula Tchen
MS3

2. Objectives
Propose & execute immediate management of shoulder Dystocia.
Describe options if immediate management of shoulder Dystocia is not successful.

3. Definition
Abnormal labour or dystocia (means difficult labour or childbirth)
Occasionally referred to as failure to progress.
A vaginal delivery is complicated by shoulder dystocia when, after delivery of the fetal head, additional obstetric maneuvers beyond gentle traction are needed to enable delivery of the fetal shoulders.
*leading indication for primary C/S in the US
variability in the diagnosis, management and criteria for dystocia
Rarely diagnosed with certainty

4. Pathophysiology of shoulder dystocia
During delivery the anterior shoulder should slide under the symphysis pubis. If the fetal shoulders remain in an anterior- posterior position during descent or descend simultaneously rather than sequentially into the pelvic inlet, then the anterior shoulder can become impacted behind the symphysis pubis; the posterior shoulder may be obstructed by the sacral promontory. Anterior obstruction is more common than posterior obstruction. If descent of the fetal head continues while the anterior or posterior shoulder remains impacted, then stretching of the nerves in the brachial plexus may occur and may result in nerve injury.
If fetal head is turned to one side (asynclitism) or extended (extension) the cephalic diameter is increased. Brow presentation can cause dystocia if it does not convert to vertex or face.

5. Epidemiology of shoulder dystocia
.2-3% of all births
Can you predict a shoulder dystocia?
NO! most often cannot predict and occur in the absence of risk factors.

6. Factors that contribute to normal labour
What are the factors that contribute to normal labour?
Power
Passenger
Position
Passage: maternal factors: shape of pelvis or soft tissue abnormalities.
Clinical radiographic and CT measurements of the pelvis are poor predictors and inaccurate
Soft tissue causes: morbid obesity, distended bladder, fibroids, accessory uterine horn, lesions of colon or adnexa, abnormalities of cervix, tumors. Epidural will decrease tone of pelvic floor and can contribute to dystocia
Ineffective uterine contractions will contribute to dystocia- monitor with tocometry

7. Risk Factors Increased fetal birthweight
Increased risk with weight over 4000g. Macrosomia is >4500g. With increasing weight, risk will increase.
Post-term, excessive weight gain during pregnancy>35lbs, parity
Diabetes
Midforceps delivery
Prolonged first/second stage?
Prior shoulder dystocia
Maternal height: more risk among shorter parturients <150cm
More permanent injuries occur among macrosomic infants but the majority of shoulder dystocias occur with infants of normal weight

8. Diagnosis Head to body delivery time exceeding 60s
Friedman’s curve to assess labour
Abnormal labour patterns:
1)prolonged latent phase; more than 20 hours in nulliparous or 14h in multiparous.
2)active labour: cervix dilates less than 1cm/hour nulliparous or less than cm/hour multiparous

9. Management Reduction maneuvers – HELPERR Mnemonic Call for Help
Evaluate for Episiotomy
Legs (McRoberts Maneuver)
Suprapubic Pressure
Enter maneuvers (internal rotation)
Removal of the posterior arm
Roll the patient
Episiotomy: Consider when dystocia is encountered – episiotomy won’t release the bony impaction, but it helps to increase room for physicians as they do internal maneuvers.
McRoberts: Ideal first step, proven effectiveness – rotates the symphysis and flattens the sacral promontory. If successful, the delivery should work with simple traction.
Suprapubic pressure: accentuates the passage of the shoulder under the symphysis – should be done with McRoberts.
Enter maneuvers: May require episiotomy. Rubin II = rotate anterior shoulder towards foetus chest. If unsuccesful, do Woods corkscrew (upward pressure on anterior aspect of posterior shoulder). Always continue traction during maneuvers
Removal of the posterior arm: find arm, flex elbow, sweep on chest wall and deliver it. If you can’t reach the elxbow you can also grasp the axilla.
Roll patient: Rolling pt on all fours (Gaskin maneuver) is safe and rapid as helps reduce shoulder dystocia by increasing the pelvic diameter

10. Management - Rubin

11. Management – Wood’s corkscrew

12. Management Reduction maneuvers – HELPERR Mnemonic
What we’re trying to accomplish:
Increase functional size of the bony pelvis
Decrease the bisacromial diameter (breadth of the shoulders)
Change the relationship of the bisacromial diameter within the bony pelvis

13. http://www.youtube.com/watch?v=j_bibDLPW98&noredirect= 1
Management 1

14. Management If those maneuvers fail: Last resort:
Deliberate clavicule fracture
Zavanelli maneuver
General anesthesia
Cesarian section
Symphysiotomy
Clavicule fracture: reduces shoulder-to-shoulder distance
Zavanelli maneuver: cephalic replacement followed by cesarean delivery – essentially you put the baby back in and go to the OR
GA: May bring enough uterine relaxation to help delivery
Abdominal surgery with hysterotomy: cesarian section (foetus is rotated transabdominally)
Symphysiotomy: LAST RESORT, not really used here, only when all other maneuvers have failed and c-section isn’t available

15. Prophylactic management
Typically, you can’t predict, so you can’t prevent!
(ACOG) Task Force on Neonatal Brachial Plexus Palsy clinical situations as high risk for shoulder dystocia and brachial plexus injury:
Estimated fetal weight >5000 g in women without diabetes or >4500 g in women with diabetes
Prior shoulder dystocia, especially with a severe neonatal injury
Midpelvic operative vaginal delivery of a fetus with estimated weight >4000 g
*Cesarean section is a reasonable option for these patients, but is discussed as a case by case basis.
Estimated weight: difficult to evaluate
- Induction not recommended for estimated high birth weight – studies show it doesn’t prevent shoulder dystocia in comparison to expectant management
Prior dystocia: uptodate suggests a c-section, but there are no official guidelines or studies to show the overall outcome. Factors such as high estimated birth weight and gestational diabetes should be taken into account, but basically this is a perfect example of shared decision making.

16. Complications Remember: diagnosis and timing are key Why?
Avoid complications:
Fetal:
Asphyxia
Cortical injury due to cord compression and asphyxia
Transient/permanent brachial plexus palsy
Clavicular or humeral fracture
Death
Maternal:
Hemorrhage
Fourth degree lacerations
Cord pH drops with increasing head-to-body-interval, but the drop does not become clinically significant for about 5 minutes.[15, 16] A 6-minute head-to-body interval has been demonstrated not to be a risk factor for hypoxic ischemic encephalopathy (HIE).[17] Beyond that time, there is increased risk of neonatal depression, acidosis, asphyxia, central nervous system damage, and death.[18, 19, 20]

17. Clinical case: Shoulder dystocia
A 30 yo G2P1 is delivering at 41 weeks gestation. She is moderately obese, but the fetus appears to clinically weigh approximately 3700 g. After a 4-hour first stage of labor and 2- hr second stage of labor, the fetal head delivers but is noted to then retract back toward the patient’s introitus (turtle sign). The fetal shoulders do not deliver, despite strong maternal pushing.
Diagnosis
Risk Factors
Management Principles of this Obstetric Emergency/ Initial Maneuvers to manage this condition
Review Neonatal and Maternal Complications of this event
Discussion point fetal weight (passenger) estimation is inaccurate. If weight is greater than g the risk of dystocia including shoulder dystocia and fetopelvic disproportion is greater. Fetal macrosomia defined as birthweight over 4500g(ACOG)
2 hour second stage- for multiparas we limit to one hour or 2 hours with regional analgesia- for nulliparas limit to 2 h or 3 h with regional analgesia
Rates of chorioamnionitis, PPH, instrumental delivery, Cesarean section and perineal trauma increase with increasing length of the active second stage of labour.
What is significance of turtle sign? May herald shoulder dystocia
Risk factors in this case : maternal obesity, pelvis- anatomy unknown. No prior history of dystocia in this case. No history of diabetes. Mother’s height unknown.

18. Case discussion
fetal weight (passenger) estimation is inaccurate. If weight is greater than g the risk of dystocia including shoulder dystocia and fetopelvic disproportion is greater. Fetal macrosomia defined as birthweight over 4500g(ACOG)
2 hour second stage- for multiparas we limit to one hour or 2 hours with regional analgesia- for nulliparas limit to 2 h or 3 h with regional analgesia
Rates of chorioamnionitis, PPH, instrumental delivery, Cesarean section and perineal trauma increase with increasing length of the active second stage of labour.
What is significance of turtle sign? May herald shoulder dystocia
Risk factors in this case : maternal obesity, pelvis ?- anatomy unknown (mother is G2 but first baby premature). No prior history of dystocia in this case. No history of diabetes. Mother’s height unknown.

19. References
Baxley, E; Gobbo, R. Shoulder Dystocia 2004 American Family Physican, 69(7), p
Beckmann et al. Obstetrics and Gynecology. 7th edition Lippincottt Williams & Williams.
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