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Shoulder dystocia

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Shoulder dystocia
Cord prolaspe
Uterine rupture
Placental abruption

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Shoulder dystocia needs to be distinguished from a mere difficulty with delivery of the shoulder. The latter occurs because of the prevailing delivery practice, with the mother in a semi-recumbent position on the delivery bed. There may be insufficient room for appropriate lateral i.e. downward flexion for delivering the anterior shoulder. In addition, the weight of the mother is in part taken on the sacrum which is therefore pushed upwards, thus decreasing the antero-posterior diameter of the pelvic outlet. Many of these cases require only a positional change, into left lateral, or kneeling, which frees the sacrum and allows lateral flexion.

Proper shoulder dystocia occurs when there is disproportion between the bisacromial diameter of the fetus and the anterioposterior diameter of the pelvic inlet. This results in the anterior shoulder becoming impacted behind the symphysis pubis (Reference1)


Maternal birth weight
Prior shoulder dystocia*
Prior macrosomia
Pre-existing diabetes
Prior gestational diabetes
Advanced maternal age

Excessive maternal weight gain***
Short stature

Prolonged second stage
Protracted descent
Failure of descent of head
Abnormal first stage
Need for midpelvic or assisted delivery

* Reccurrence rate of between 10-13.8% (Reference3,Reference4)
** Mothers that weigh more than 81kg experience 30% of all shoulder dystocias(Reference5) (RR x8) (Reference6)
*** More than 20kg gain showed an increase in shoulder dystocia from 1.4% to 15.2% (Reference7)

Diabetic mothers have a threefold increased risk of shoulder dystocia because of a disproportionate increase in fetal abdominal circumference to head circumference (Reference8). The presence of maternal diabetes together with macrosomia (defined here as > 4kg) is estimated to result in shoulder dystocia in a third of those delivering vaginally (Reference9)

However, the event is difficult to predict, as half of all instances of shoulder dystocia occur in babies weighing less than 4kg (Reference10). Furthermore, of the babies which do weigh over 4 kg, most are not detected as such clinically. Even an ultrasound scan often misses these babies because of its low sensitivity (60%) of detection of macrosomia in the third trimester (Reference8).

Inducing the suspected large babies only increases the intervention rate and will not decrease the incidence of shoulder dystocia (Reference11). A policy of caesarean sections for those babies predicted antenatally to weigh more than 4.2 kg increases the section rate but does not have a significant impact on the rate of shoulder dystocia (Reference11). A prophylactic caesarean section policy on babies of 4-4.5kg would require more than a thousand sections to avert one brachial plexus injury (Reference8).

5th CESDI report

56 cases were reviewed in 1996 which resulted with the death of the baby. The focus group found 66% of cases to have Grade 3 suboptimal care where a "different management could reasonably have been expected to have altered the outcome". 36% of the babies were born to primigravidas and although 40% were predicted to be large babies, these were often not flagged up as potential problems. Maternal obesity was noted, with 11% of the mothers having a BMI of > 40. The overall induction rate was 36%.

Conclusions :

  • Anticipate the problem, look out for signs and risk factors
  • Senior staff (including paediatricians) should be called immediately. Guidelines should make this clear
  • McRoberts manoeuvre should be carried out with suprapubic pressure
  • Failure of the above means it is reasonable to carry out the all fours manoeuvre or squatting positions if obstetric assistance is not yet available
  • The next step is delivery of the posterior shoulder
  • Complete and accurate notekeeping is crucial
  • Regular updates on the local protocols is helpful
  • Staff should be aware of the procedures of symphysiotomy, clavicular fracture and /or the Zavenelli procedure if desperate measures are called for.

If we are unable to avoid this emergency, it is vital to be clear on the management of shoulder dystocia in order to act quickly and efficiently. Adequate training and guidelines are essential.


1. Early recognition / raised level of suspicion:

Large baby, post dates, large maternal BMI, maternal diabetes, previous history of shoulder dystocia; prolonged 2nd stage, turtle neck sign

2. Call appropriate staff:

  • Senior midwife
  • 2nd midwife
  • senior obstetrician
  • anaesthetist
  • paediatrician
  • Explain to the patient and family what is happening

3. NB

Is this a proper shoulder dystocia, or is it caused by maternal posture, with sacrum pushed up, leaving not enough room at the outlet? In this case consider left lateral position, or, (in the absence of an epidural), squatting or kneeling (all fours). (Reference12)

4. Mc Roberts position:

Femora are abducted, rotated outwards and flexed, so that thighs touch the mother's abdomen, with the aid of two assistants. The buttocks need to come over the edge of the bed, allowing the sacrum to rotate backwards.

Apply suprapubic pressure: Another assistant puts hand laterally and pushes in direction that the baby is facing and posteriorly to try and disimpact the anterior shoulder. This is done at the same time as moderate traction of head. 91% of cases will be delivered by this stage (Reference13).

5. Make or enlarge episiotomy:

This enables access to the vagina for step 6 or 7

Please note: there is NO place for fundal pressure or undue traction on the head. The brachial plexus is already under stretch and further traction results in neurological damage. Fundal pressure can only increase impaction of the shoulder under the symphysis pubis (Reference10).

6. Woods screw manoeuvre:

Rotation of the posterior shoulder by 180 degrees to deliver the anterior shoulder from under the symphysis pubis (Reference14). Rubin's manoeuvre is turning the baby in the opposite direction (reverse Woods manoeuvre). This has the advantage of abducting the shoulders, thereby decreasing the diameter (Reference15).


7. Delivery of posterior arm:

insert hand into sacral hollow to identify the posterior shoulder, arm down to the wrist. Sweep this across the fetal chest, flexing the elbow, to deliver the arm posteriorly.

8. Zavanelli manoeuvre (cepahalic replacement):

Manual return of the partially born, but undeliverable, fetus to the vagina for extraction by caesarian section (Reference16). This is done by rotating the head back to the occiput anterior position, flexing the head with pressure on the occiput whilst using the other hand to replace the chin back into the vagina. Tocolytics can help the procedure (terbutaline 0.25mg sc)



division of the fibrocartilagenous symphysis pubis (Reference17). Using local anaesthetic, infiltrate the joint with the patient in the lithotomy position (thighs supported at no more than 90 degrees, so as not to put too great a strain on the sacroiliac joints). Use the index and middle fingers of the left hand on the posterior aspect of the symphysis. Push the indwelling catheter aside with the index finger and use the middle finger to monitor the action of the scalpel. The latter is used like a pencil, keeping it vertical and, using the entry point as a fulcrum, to bring the blade down towards the operator. Remove, turn 180 degrees and in original point to divide the upper half of the symphysis. If completed, the middle finger can fit into the space created by the separation.

Step 8 is only if all the above manoeuvres have failed. The CESDI recommendations state that clinicians should be aware of these if desperate measures are sought. We are unlikely to see an RCT in either procedure.

Important to have accurate record keeping:

  • Time head delivered
  • Time each manoeuvre was performed
  • Time body delivered
  • Staff present
  • Need for regular scenario training and ward drills

Regular audit of shoulder dystocia cases, irrespective of the outcome


1. Roberts L. Shoulder dystocia. Progress in Obstetrics and Gynaecology. Volume 11: chapter 12:201-16.
2. O'Leary JA, Leonetti HB. Shoulder dystocia: Prevention and treatment. Am J Obstet Gynecol 1990;162:5-9, Abstract
3. Smith RB. Shoulder dystocia: what happens at the next delivery? Br J Obstet Gynaecol 1994;101:713-5.43, Abstract
4.Lewis, Recurrence rate of shoulder dystocia. Am J Obstet Gynecol 1995;172(5):1369-71, Abstract
5. Seigworth G. Shoulder dystocia. Obstet Gynecol 1966;28:764-7.
6. Schwartz B. Shoulder dystocia. Obstet Gynecol 1958;11:468-71.
7. Boyd ME, Usher RH. Fetal macrosomia: prediction, risks, proposed management. Obstet Gynecol1983;61:715, Abstract
8. Rouse D. Prophylactic caesarean delivery for fetal macrosomia diagnosed by means of ultrasonography - a Faustian bargain? Am J Obstet Gynecol 1999;181:332-8, Abstract
9. Johnstone F. Shoulder Dystocia. Br J Obstet Gynaecol 1998;105:1256-61, Abstract
10. CESDI 5th Annual Report published by the Maternal and Child Health Research Consortium in May 1998.
11. Weeks J. Fetal macrosomia: does antenatal prediction affect delivery route and birth outcome? Am J Obstet Gynecol 1995;173:1215-9, Abstract
12. Luria S. The ABC of shoulder dystocia management. Asia-Oceania J Obstet Gynaecol 1994;20:195-7, Abstract
13. Woods CE. A Principle of physics as applicable to shoulder delivery. Am J Obstet Gynaecol 1943;45:796-804.
14. Rubin A. Management of shoulder dystocia. JAMA 1964;189:835.
15. Bruner JP. All-Fours Maneuver for reducing shoulder dystocia during labor. J Reprod Med 1998;43:439-43, Abstract
16. Sandberg E. The Zavanelli Maneuver: 12 years of recorded experience. Obstet Gynecol 1999;93:312-7, Abstract
17. Menticoglou SM. Symphysiotomy for the trapped aftercoming parts of the breech: A review of the literature and a plea for its use. Aust NZ J Obstet Gynaecol 1990;30:1-9, Abstract

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