Delivery cannot progress after the head is out, because the shoulders are impacted in the pelvis.
This is a life-threatening emergency for the foetus (distress, rapid death by asphyxiation).
Additional assistants are required. Explain the situation to the assistants and the patient to obtain their cooperation.
The HELPERR mnemonic is a useful tool for addressing this emergency
Elizabeth G. Baxley, Robert W. Gobbo. Shoulder Dystocia. Am Fam Physician. 2004 Apr 1;69(7):1707-1714.
Call for Help
Evaluate for Episiotomy
Legs (the McRoberts manoeuvre)
Enter manoeuvres (internal rotation)
Remove the posterior arm
Roll the patient
H: Call for help.
E: Evaluate for episiotomy
Episiotomy is not routinely needed since the shoulder is impacted on the bony pelvis. However, it can be performed to make more room for manoeuvres.
The recommended time for attempting manoeuvres is 30 to 60 seconds each. An assistant should inform the operator how much time has passed.
L: McRoberts manoeuvre (hyperflexion of the mother's thighs)
Ask two assistants to push the patient’s knees firmly toward her chest. This manoeuvre alone is effective in releasing a shoulder in more than 70% of cases.
P: Suprapubic pressure
While maintaining the hyperflexion of the thighs, an assistant presses firmly just above the symphysis pubis to try to reduce the diameter of the shoulders and lower the anterior shoulder under the symphysis while the operator applies continuous downward traction on the foetal head. Do not apply fundal pressure, as this will impact the shoulder and can result in uterine rupture.
E: Internal manoeuvres
If this fails, perform internal rotation manoeuvres while maintaining the hyperflexion of the thighs. There are several options, depending on whether there is easier access to the anterior or posterior shoulder:
- Rubin’s manoeuvre: insert the fingers of one hand behind the anterior shoulder and push toward the foetal chest to try to free the shoulder.
- Wood’s corkscrew manoeuvre, to be combined with Rubin’s manoeuvre: place two fingers of the free hand against the front of the posterior shoulder and apply pressure to free the shoulders by turning (in a corkscrew manner).
- Reverse Wood’s corkscrew manoeuvre: similar, but rotating in the opposite direction.
R: Remove the posterior arm
If this fails, bring down one foetal arm to reduce the diameter of the shoulders and allow delivery:
- Kneel to get the proper axis of traction.
- Reach in to find the posterior arm, and bring it to the vaginal opening: slide the whole hand behind the foetus' head and move it along his posterior arm up to his elbow (if the back of the foetus is toward the operator's right side, the left hand is used, if the back is toward the operator’s left side, the right hand is used). Bend the arm and grasp the forearm or wrist and draw across the foetal chest to the vaginal opening. The delivery can then continue.
R: Roll the patient onto her hands and knees
Roll the patient to “all-fours position”. The pelvic diameters increase in this position.
Carefully examine the vagina after these manoeuvres, since lacerations are common.
Above all, do not:
- Apply excessive traction to the foetal head, as this can rupture the brachial plexus on the side of the anterior shoulder.
- Pivot the head by twisting the neck, as this can also cause neurological injury.
7.5.2 Methods of last resort
- General anaesthesia to relax the muscles.
- Fracture of the foetal clavicle by direct pressure on the middle part of the clavicle (difficult to perform deliberately).
- Symphysiotomy (Chapter 5, Section 5.7).
- Embryotomy in case of foetal death and failure of the manoeuvres (Chapter 9, Section 9.7).
- Push the head back in (very difficult), then perform caesarean section.