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Understanding the risks and being prepared can help you feel more confident and supported if shoulder dystocia occurs during your delivery.
What is Shoulder Dystocia?
Shoulder dystocia is a rare but serious complication that can occur during vaginal delivery. It happens when the anterior shoulder of your baby becomes lodged behind your pubic symphysis (the front pelvic bone) after the head has been delivered. Or less commonly, the posterior shoulder gets stuck on the sacral promontory (a part of your lower spine). This prevents the baby from being born. It’s considered an emergency because a delay can lead to complications for you and your baby. The incidence could roughly be 0.15 to 1.1 per cent in vaginal deliveries, with rates increasing for babies weighing over 4,000 grams.Causes of Shoulder Dystocia
Shoulder dystocia happens due to a mismatch between your baby’s size or position and the space in your pelvis. The main causes include:- Large baby (foetal macrosomia): If your baby weighs more than 4,000 grams, their broader shoulders may not fit easily through your pelvic outlet.
- Baby’s position: Your baby can get stuck if their shoulders remain in an anterior-posterior position instead of rotating to the wider oblique angle of your pelvis.
- Small or abnormal pelvic opening: A narrower pelvis or unusual pelvic shape can limit the space for your baby’s shoulders to pass through.
- Maternal position: Certain positions during labour might restrict the room in your pelvis and contribute to the issue.
Risk Factors for Shoulder Dystocia
Some of the risk factors can make shoulder dystocia more likely. These can be divided into those present before labour and during labour:Pre-Labour Risk Factors
- Previous shoulder dystocia: If you’ve had this complication before, the risk increases in future pregnancies.
- Foetal macrosomia: Babies weighing over 4,000 to 4,500 grams.
- Diabetes: Both pre-existing and gestational diabetes double the risk, as people with diabetes may have babies with macrosomia.
- Maternal obesity: A body mass index (BMI) over 30 or excessive weight gain during pregnancy.
- Induction of labour: This can indirectly increase the risk, especially if done for suspected macrosomia.
- Postterm pregnancy: Babies born after your due date may be larger and increases the chance.
- Maternal age: Being over the age of 35.
- Short stature or abnormal pelvic structure: A smaller or unusually shaped pelvis can complicate delivery.
- Multiple babies: Carrying twins or more.
Risk Factors During Labour
- Prolonged first stage: A slow initial phase of labour can be a factor.
- Secondary arrest: When labour progress stops due to your baby’s position.
- Prolonged second stage: When you are fully dilated and pushing for too long.
- Precipitous second stage: A very fast pushing phase, less than 20 minutes, can also pose a risk.
- Assisted vaginal delivery: Using forceps or a vacuum extractor to assist in delivering the baby.
- Oxytocin use: Use of this medication to augment labour.
- Epidural: This pain relief method may be linked to a higher risk.
Signs of Shoulder Dystocia
You won’t feel shoulder dystocia directly, but your healthcare professional may notice these signs during labour:- Difficulty delivering shoulders: After your baby’s head is out, the shoulders don’t follow despite normal traction.
- Turtle neck sign: Your baby’s head emerges but then retracts slightly back against your perineum (area of skin between the anus and the genitals), like a turtle pulling into its shell.
- Failure of restitution: Normally, your baby’s head turns to the side after delivery to align with the body, but here it stays facing forward.
- Prolonged labour: The pushing phase may take longer than expected, with increased pain or pressure.
- Foetal heart rate changes: Abnormal patterns might signal distress.
Diagnosis of Shoulder Dystocia
Your obstetrician diagnoses shoulder dystocia during labour based on clinical signs. They’ll evaluate labour progress, your medical history, and examine how delivery is unfolding. The diagnosis is confirmed if more than 60 seconds pass after the baby’s head is delivered, but the body hasn’t. This may require extra manoeuvres.A third-trimester ultrasound can help identify macrosomia, which increases the risk of shoulder dystocia. However, it has low accuracy in predicting whether shoulder dystocia will occur.
This complication is hard to detect, and mild cases might go unnoticed. No clear symptoms show up before the head emerges, which makes it a challenge to predict beforehand.
Management of Shoulder Dystocia
Your healthcare professional acts quickly to deliver your baby safely if shoulder dystocia occurs:- Stop pushing: You’ll be asked to pause pushing to avoid worsening the impaction.
- Avoid harmful actions: No downward traction on the head or fundal pressure (pushing on your abdomen), as these risk injury or uterine rupture.
- Episiotomy: A small cut to your perineum might be made. Not to free the shoulder but to allow better access for manoeuvres.
First-Line Manoeuvres
- McRoberts manoeuvre: You’ll flex your thighs tightly against your belly, widening your pelvis and flattening your spine. This resolves most of the cases, especially with suprapubic pressure.
- Suprapubic pressure: A nurse applies firm, lateral, or rocking pressure above your pubic bone to dislodge the shoulder, alongside the McRoberts manoeuvre.
Second-Line Manoeuvres
- Posterior arm delivery: Your doctor inserts a hand into the vagina to reach your baby’s posterior arm and carefully moves it across the chest, freeing it first to create space.
- Corkscrew manoeuvre: Pressure is applied to turn your baby’s shoulders 180 degrees or into an oblique position for easier delivery.
- Gaskin manoeuvre: If needed, you may roll onto your hands and knees to widen your pelvis.
After Delivery
- Active management during the placental stage (third stage of labour) is important because it helps prevent postpartum haemorrhage, which is a common risk following shoulder dystocia during delivery.
- A rectal check looks for severe tears, and a paediatrician assesses your baby for injuries.
- Your doctor will explain what happened during the delivery, discuss recurrence risks, and offer support, as this experience can be traumatic.
- A physiotherapy review may help with pelvic floor weakness, pain, or nerve issues.
Complications of Shoulder Dystocia
Shoulder dystocia can lead to issues for you and your baby if not handled well:Maternal Complications
- Postpartum haemorrhage.
- Third or fourth degree tears to your perineum.
- Rectovaginal fistula (an abnormal connection between your vagina and rectum).
- Uterine rupture during labour.
- Pubic bone separation.
Foetal Complications
- Brachial plexus injury: Nerve damage that affects movement or sensation in the arm. It may be temporary, but sometimes long-lasting.
- Fractures: A fracture of your baby’s clavicle (collarbone) or humerus (upper arm bone). These fractures usually heal with the use of braces or casts.
- Horner’s syndrome: A rare issue affecting one side of your baby’s face and eye. Signs include a drooping eyelid, a smaller pupil, and less sweating on that side of the face.
- Umbilical cord compression: The umbilical cord becomes compressed, which reduces oxygen and blood flow to the baby.
- Hypoxic brain injury: When the baby’s oxygen supply is interrupted during a difficult delivery, it can potentially cause brain damage.
Prevention Strategies for Shoulder Dystocia
Shoulder dystocia can’t always be prevented, but you can lower your risk by following these prevention strategies:- Manage diabetes: Control pre-existing or gestational diabetes with diet, blood sugar monitoring, and insulin if needed to reduce macrosomia.
- Healthy weight: Maintain a balanced weight and avoid gaining over 11 to 12 kgs during pregnancy.
- Prenatal care: Regular check-ups monitor your baby’s growth and your health.
- Discuss induction: Ask your obstetrician about inducing labour if you’re past your due date.
- Consider a caesarean section: If you have diabetes, a large baby, or past shoulder dystocia, a planned caesarean might be an option.
- Limit medications: Talk to your doctor about avoiding epidurals or oxytocin if possible.
Shoulder dystocia happens without warning and can affect anyone, even those with no clear risk factors. You can't always prevent it, but understanding its causes and signs helps you prepare better. Remember to control your diabetes and regularly attend prenatal checkups to reduce the risk of this complication.
FAQs on Shoulder Dystocia During Childbirth: What You Need to Know
- What causes shoulder dystocia?
It is mainly caused by a mismatch between the baby’s size or position and the space in the mother’s pelvis. Common causes include a large baby, unusual pelvic shape, or certain labour positions. - What are the risk factors for shoulder dystocia?
Risk factors include a previous shoulder dystocia, a large baby, diabetes, maternal obesity, or carrying multiple babies.
