Shoulder Dystocia During Childbirth

Shoulder dystocia is a rare condition that can sometimes be seen during delivery after the head of the foetus has emerged from the mother’s body. The baby’s shoulder (left or right) stays back behind the mother’s pubic bone and results in pressure. Occasionally, the baby’s posterior shoulder puts pressure on the mother’s sacrum (large bone at the base of the spine). If either of these cases occurs, the rest of the baby’s body does not come out easily. This complication is termed Infant Shoulder Dystocia.

What is Shoulder Dystocia?

Shoulder Dystocia is defined as an obstetric complication which is associated with cephalic vaginal deliveries where the baby’s head enters the pelvis first. It happens only when the baby’s shoulders get stuck after the head emerges from the mother’s vagina. Infant shoulder dystocia happens when one or both the shoulders are placed in a direction opposite to the maternal pelvis bones.

Causes of Shoulder Dystocia

• Macrosomia: It is a condition in which the newborn baby has excessive birth weight. Babies with more weight than general cases tend to have a heavy body which can make vaginal delivery difficult.
• Abnormal Pelvic Anatomy: There are chances that a small pelvis would result in the baby getting stuck.
• Gestational Diabetes: This increases the chances of the baby putting on weight on the torso, which may come in the way of a smooth passage through the birth canal
• Post-dated Pregnancy: Prolonged stay of the baby in a mother’s womb tends to the increased overall growth of the baby leading to difficult vaginal delivery.
• Assisted vaginal delivery utilising Forceps or Vacuum: This may result in a brachial plexus injury to the infant. These are the bundle of nerves which connect the spine to the shoulder, arm and hand
• Labour Abnormalities: Delayed dynamic period of first stage labour when the cervix dilates to about 8 cm, and prolonged second stage labour, can also cause brachial plexus injury. Having induced labour can also increase the risk of this condition
• Oxytocin and Anaesthesia: While there is no data to establish a correlation between the use of oxytocin and anaesthesia to shoulder dystocia, there is an indirect connection which is seen as a risk factor. Oxytoxin is used for macrosomic babies, and, as mentioned above, large babies are more prone to the condition

Shoulder Dystocia signs and symptoms

Mothers can experience symptoms ranging from bruising of the bladder, rectum, vagina, or cervix, or even haemorrhaging.

The baby faces difficulties in emerging with normal traction and may require the mother to give extra pressure to push the remaining part of the body out.

Turtle Sign in Shoulder Dystocia: A major complication and a major sign faced during shoulder dystocia is when the foetal head suddenly retracts against the mother’s perineum after emerging out of the vagina. This leads to bulged cheeks of the infant. This occurs because the shoulder of the infant is not able to emerge from the mother’s pelvic cavity with the pressure developed inside. The condition is so named as it resembles a turtle putting its head back into the shell.

Diagnosis

No anticipation or predictions can be made before the birth of the possibility of shoulder dystocia occurring. The helpers need to make a quick diagnosis of this condition and react instantly.

Shoulder Dystocia Complications

This condition causes severe complications in both the mother and the infant, ranging from:

Mother:

• Postpartum haemorrhage which is excessive bleeding within 24 hours of childbirth
• Cervicovaginal lacerations which are tears in the cervix and vagina during labour and delivery
• Rectovaginal fistula where a connection opens up between the lower part of the large intestine and the vagina which may cause stool and gas to pass into it
• Lacerations of the rectum which are cuts in the anal tissue
• Symphyseal separation or diathesis, which is an abnormally large gap between the pubic bones after delivery
• Third- or a fourth-degree episiotomy where the laceration extends into the muscle that surrounds the anus or uterine wall rupture
• Bladder atony which is the inability to control the bladder function

Infant:

• Brachial plexus palsy (Erb’s palsy) which is the loss of function of the shoulder and arm because of damage to the nerves that link them to the spine
• Broken collarbone (clavicular fracture)
• Foetal death
• Foetal hypoxia (decreased oxygen supply) with or without permanent neurologic damage
• Wounds, which are bruises on the skin where the blood capillaries have ruptured
• Humeral fracture, which is a broken bone in the upper arm

Who Is at Risk for Shoulder Dystocia?

Some of the common shoulder dystocia risk factors include:

• Maternal obesity and age over 38 years
• Excessive prenatal weight gain
• Maternal diabetes
• Protracted labour which is slow progress of labour when the cervix does not dilate at the expected speed or the baby does not descend as expected
• Foetal macrosomia or large baby
• Multiparous women; women who have given birth multiple times, or are carrying multiple babies
• Previous history of shoulder dystocia
• Short-statured women

How Is Shoulder Dystocia Treated and Managed?

A widely applicable treatment strategy followed by obstetricians can be understood by the Pneumonic “HELPERR”:

H – Calling for help by physician

E – Evaluating episiotomy (small vaginal incision)

L – Legs (The doctor may ask the mother-to-be to pull her legs toward the stomach. This is also called the McRoberts manoeuvre)

P – Suprapubic pressure (The baby will be encouraged to rotate by putting pressure on a specific area of the pelvis)

E – Entering manoeuvers procedure (internal rotation) (This involves turning the baby’s shoulders in the womb to help the movement through the pelvis

R – Removal of posterior arm from birth canal (This involves freeing one arm from the birth canal)

R – Rolling of patient (The doctor may ask the mother-to-be to get down on all fours to help the  movement of the baby)

Let’s understand the above treatment procedure in more detail.

Manoeuvers Used for Shoulder Dystocia:

• McRoberts Manoeuver – In this procedure, the mother-to-be’s hips are flexed, and her thighs are positioned up onto her abdomen. This is done with the help of nurses and family members present in the delivery room. This position flattens the mother’s sacral promontory (inward projecting part of the sacral vertebra) by increasing the angle of inclination between the symphysis pubis (joint between left and right pubic bones). This helps orient the symphysis pubis more horizontally to facilitate delivery.
• Suprapubic pressure – This is an attempt to manually help in removing the infant shoulder from behind the symphysis pubis. It is usually performed by a helper who places a hand just above the mother’s pubic bone and pushes the posterior aspect of the infant’s shoulder in one direction or the other. Pushing the shoulder may turn the shoulder to an oblique angle which helps the delivery to be smooth and easy.
• Delivery of the posterior arm – Here, the helper places his or her hand behind the posterior shoulder of the foetus and locates the arm. This arm is then swept across the foetal chest and delivered. This allows the foetus to drop into the birth canal, freeing the shoulder. With the posterior arm and shoulder now delivered, it is relatively easy to rotate the infant, dislodge the anterior shoulder, and complete the delivery of the baby.
• Delivery of the posterior shoulder – Also called menticoglou, this involves putting a finger or soft catheter behind the posterior shoulder of the foetus to pull it downward. This enables the grasping of the posterior arm, allowing the infant to be delivered, followed by delivery of the trunk.

Secondary Manoeuver:

• Wood’s Screw manoeuver– In this procedure, the anterior shoulder is pressed toward the chest, and the posterior shoulder is pressed back to rotate the baby so that it faces backwards. This helps release the shoulder and deliver the baby.
• Rubin manoeuvre – This procedure involves pushing on the posterior surface of the posterior shoulder (counterclockwise rotation) which helps in the flexing of shoulders across the chest. This decreases the distance between the shoulders so that the size of the baby is narrowed and fits fit through the pelvis.

Last Resort Techniques:

• Deliberate fracture of the clavicle – Usually not preferred as it poses a major threat to vital organs such as vessels, lungs, etc. It is performed in a bid to save the mother’s life, only if there is a miscarriage.
• Gaskin All-fours manoeuver – This procedure involves placing the mother on her hands and knees with the back arched. This widens the pelvic outlet and facilitates delivery. This involves extended labour and is usually a hectic and cumbersome procedure leading to other maternal complications.
• Posterior axilla sling traction(PAST) – This involves the delivery of the posterior foetal arm through an incision in the uterus. The hand which is freed is pulled through the vagina by another assistant.
• General anaesthesia – Labour suppressing agents such as terbutaline, nitroglycerin, or uterine-relaxing general anaesthesia may be administered later on followed by Manoeuvers.
• Zavanellimaneuver – This involves an emergency caesarean operation. Initially, the infant’s head is rotated to the occiput front position and then rotated by using constant firm pressure, simultaneously pushing the head back into the vagina. This is followed by a caesarean immediately. Tocolytic agents (medicines that suppress labour) such as terbutaline, nitroglycerin, or uterine-relaxing general anaesthesia may be administered to facilitate this process.
• Abdominal surgery with an incision in the uterus – Here, general anaesthesia is usually followed by a caesarean incision. Later, the surgeon rotates the infant trans-abdominally through the hysterectomy incision (incision in the uterus), allowing the shoulders to rotate (similar to the Woods corkscrew manoeuver). The baby is then extracted through the vagina by another physician.
• Transabdominal shoulder rotation (“Abdominal rescue”) – An incision is made in the abdomen, to access and manually rotate the foetus’s stuck shoulders until the foetus can complete a vaginal delivery.
• Symphysiotomy – In this procedure, the cartilage of the pubic symphysis is surgically divided. This widens the pelvis and facilitates delivery. This procedure is used when all other options have been ruled out.

Are there any measures to prevent Shoulder Dystocia?

Here are a few ways to try and prevent the occurrence of shoulder dystocia

• Tracking foetal positioning and encouraging the baby to settle in the right position
• Performing exercises which flex and widen the pelvis
• Choosing mid-wives or doctors who encourage undisturbed birth
• Evaluating risk factors and proper management of risk factors in a mother can also help prevent maternal complications related to shoulder dystocia.

Recovery of Mother and Baby after Birth(Post-treatment Measures)

No special measures are required after the infant is born with a natural birth after shoulder dystocia. But if any chances of brachial plexus injury are noticed, it requires special monitoring in the neonatal section.

Another complication to watch out for is Erb’s palsy which means a numb and paralysed arm. This usually gets better in hours or days, but if prolonged, the infant may have to undergo physiotherapy.

The mother may undergo severe trauma due to the physical damage that she underwent during delivery, especially severe haemorrhage. Other emotional agonies including shock, guilt, depression, or even anger.

Many efforts have been put in by obstetricians to foresee or prevent the condition of shoulder dystocia in an infant, such as using ultrasound and various other tests to predict macrosomic infants. Multiple strategies have also been proposed to reduce infant complications such as brachial plexus injury by performing prophylactic caesarean section. Many potential medical aids and medicines have also been applied to reduce the risk and to promote safe vaginal delivery.

The HELPERR manoeuver is widely established and performed to treat shoulder dystocia and associated complications. When all these techniques fail, last resort techniques are established to prevent foetal death. The internal rotation manoeuvers help in manipulating the foetus, to escape the slumped shoulders of the foetus, and incline the foetus at such an angle that promotes a smooth vaginal delivery.

Consequently, with time and by application of these modern methods, the foetal death rate has declined. However, the complete elimination of infant complications like brachial plexus injury, Erb’s palsy, and other injuries is still tricky. Many researchers are conducting quality research initiatives to study preventive measures which can combat this problem and complications associated with it.