What is Shoulder Dystocia?
Shoulder dystocia is a complication that can happen during a vaginal birth. It happens when the baby’s shoulder gets stuck behind the mother’s pubic bone. It may also, but less commonly, occur when the baby’s back shoulder gets trapped behind the mother’s tailbone. This situation is usually noticeable because the usual gentle downward pulling doesn’t help the baby’s shoulders to come out, and extra steps need to be taken to ensure a successful delivery.
This condition is considered a birth emergency. It’s usually unpredictable and not preventable. The main goal of any recommended plan of action is to stop the baby from being deprived of oxygen and potentially suffering brain damage. That’s why any healthcare professional involved in a vaginal delivery must know how to quickly recognize shoulder dystocia and be ready to perform the extra steps needed to deliver the baby. Being competent in the recommended sequence of steps and managing the situation along with other healthcare professionals can stop permanent harm and lack of oxygen to the newborn when shoulder dystocia occurs. However, if healthcare professionals lack this knowledge, it could potentially lead to further harm to both the mother and the baby because of an unsuitable approach to handle shoulder dystocia.
Becoming better at managing shoulder dystocia and developing the knowledge, skills, and strategies to identify and effectively deal with this problem can lead to better patient outcomes and reduce risks to the mother and baby. It can also decrease the number of deaths related to this condition.
What Causes Shoulder Dystocia?
Shoulder dystocia is a childbirth complication where the baby’s shoulders get stuck in the mother’s pelvic bone during birth. Three main factors contribute to this:
* The baby might be too large to move easily through the birth canal (for instance, if the baby is unusually large)
* The baby’s chest might be wider compared to its head (often seen in babies of diabetic mothers)
* Quick labor may prevent the baby’s shoulders from adjusting properly in the pelvis (like during a fast delivery)
It’s important to note that shoulder dystocia often comes unexpectedly, and it’s hard to prevent it fully. The most common factors that increase the risk of shoulder dystocia include mother’s diabetes, previous shoulder dystocia, and large sized babies.
A mother with diabetes can have high blood sugar levels, which can influence the baby to produce more insulin and growth hormones. This might cause the baby to grow too large for its gestational age, or it could result in the baby having larger shoulders and a larger abdomen compared to its head. Such larger babies may find it hard to pass through the mother’s pelvis. Often, shoulder dystocia is seen in mothers who aren’t diabetic and have average-sized babies, and it’s also true that many diabetic mothers or mothers with large babies don’t experience shoulder dystocia.
If a woman has a past experience of shoulder dystocia, or she had given birth with the help of tools like forceps or vacuum, or her baby had shoulder complications, then her risk of facing shoulder dystocia again could be at least 10%. In such cases, it may be advised to consider a planned c-section after carefully evaluating her complete health condition. Medical practitioners need to be more alert and prepared for repeat shoulder dystocia incidents in such women. Some may suggest the use of a special technique called the McRoberts maneuver to prevent shoulder dystocia. But, it hasn’t shown any significant advantages when used before shoulder dystocia symptoms appear.
There are other risk factors too, such as previous delivery with the assistance of forceps or vacuum, giving birth to a larger baby, significant weight gain during pregnancy, obesity, and stillbirth. However, these are usually seen along with the more, considerable risk factors like large babies and maternal diabetes, making it challenging to determine the specific risk linked to each feature.
Certain conditions during labor might also hint at possible shoulder dystocia, like a longer second phase of labor, the baby’s head not descending, or the need for assistance in delivering the baby’s head. Still, while it’s crucial to be aware of these risk factors to prepare for childbirth properly, predicting shoulder dystocia based on these factors isn’t very accurate or reliable.
Risk Factors and Frequency for Shoulder Dystocia
Shoulder dystocia, a complication during childbirth, happens in about 0.2% to 3% of all vaginal deliveries where the baby’s head comes out first. As the baby’s size increases, so does the risk of shoulder dystocia. Let’s look at some specific scenarios:
- For babies weighing less than 4,000 grams (roughly 8.8 pounds), the risk of shoulder dystocia is about 1%.
- This risk increases to around 5% to 9% for babies weighing between 4,000 and 4,500 grams (roughly 8.8 to 9.9 pounds).
- For babies heavier than 4,500 grams (more than roughly 9.9 pounds), the risk rises to about 14% to 23%.
Signs and Symptoms of Shoulder Dystocia
When a pregnant woman is admitted to the hospital, the medical team collects detailed information about her health, obtains a physical examination, and reviews all medical imaging. They do this to spot potential risk factors that might complicate the pregnancy or delivery. These risk factors could include:
- The mother having diabetes, being overweight, or gaining a lot of weight during the pregnancy
- A past experience of shoulder dystocia (a complication during birth when the baby’s shoulder gets stuck)
- The baby being especially large – weighing an estimated 11 lbs (5,000 grams) or more in a mother without diabetes, or 9.9 lbs (4,500 grams) or more in a mother with diabetes
Throughout labour and delivery, it’s crucial for the healthcare provider who is delivering the baby to keep an eye on the baby’s position and progress as it moves into the birth canal. This information will help them carry out the right procedures if shoulder dystocia occurs.
In some cases, following the delivery of the baby’s head, the head might retract back towards the birth canal – this is often called the “turtle sign” and could indicate shoulder dystocia is about to happen. However, it’s not a conclusive sign. A definite diagnosis of shoulder dystocia typically relies on one of these criteria:
- The healthcare provider can’t deliver the baby’s shoulders using gentle downward force
- Extra birth techniques are needed to deliver the baby safely
- The time between the delivery of the baby’s head and body is longer than a minute
Testing for Shoulder Dystocia
Pelvimetry is a technique used to measure the size and dimensions of the pelvis. This is often done for pregnant individuals to check for the risk of their baby being too big to pass through their pelvis, a condition known as cephalopelvic disproportion. There are three main measurements or distances taken, known as diameters: anterior-posterior, transverse, and oblique. The anterior-posterior measurement can also be taken in three different ways, giving different sub-measurements known as conjugates.
The ‘anatomic conjugate’ is the distance from the top of the pubic bone to a point on the sacrum at the bottom of the spine. If this measurement is less than 12 cm, it may increase the likelihood of needing a cesarean delivery due to difficulties during labor.
The ‘diagonal conjugate’ is measured from the bottom of the pubic bone to the sacrum, and it’s the only measurement that can be taken via a physical examination. During the examination, the doctor can feel for the sacrum with their middle finger and then note the distance to where their hand meets the pubic arch.
The ‘obstetric (or true) conjugate’ measures between the sacrum and the widest part of the pubic bone. While this can’t be measured directly during an examination, it can be estimated. This measurement is vital as it represents the smallest fixed distance through the pelvis.
While some studies suggest using ultrasound imaging to measure the obstetric conjugate, current guidelines don’t typically recommend making delivery decisions based on these measurements. This is because studies have found no evidence that this improves outcomes.
During labor, there may be signs of a possible complication called shoulder dystocia. This includes extended labor, the baby’s head not descending, and needing assistance to deliver the baby’s head. However, trying to predict shoulder dystocia based on these risk factors has proven to be unreliable.
Shoulder dystocia is typically diagnosed after it happens, such as when the baby’s shoulders don’t deliver with gentle downward pushing, or when additional steps need to be taken. In these scenarios, the rest of the delivery team should be informed of the situation. Following delivery, both the mother and the baby must be carefully checked for any potential injuries.
Treatment Options for Shoulder Dystocia
Shoulder dystocia is a medical emergency during childbirth which requires careful coordination and skill from the doctor and the medical team to swiftly but cautiously deliver the baby while minimizing the risk to the mother and the newborn. The situation occurs when the baby’s shoulders get stuck inside the mother’s pelvis during delivery.
When shoulder dystocia is identified, the doctor needs to clearly communicate it to the medical team, so they can bring in additional help if needed and start documenting the procedure. The doctor then performs a series of techniques, categorized as first-line, second-line, and heroic maneuvers, to safely deliver the baby. Importantly, the mother should be instructed to stop pushing during these maneuvers, and no pressure should be applied to the top of the uterus as it doesn’t aid the delivery and might increase the risk of complications.
First-Line Maneuvers include the McRoberts maneuver and suprapubic pressure. In the McRoberts’ maneuver, the mother’s legs are flexed back towards her stomach to increase the pelvic outlet, creating more space for the baby. Supplementing this maneuver with suprapubic pressure can help to dislodge the baby’s shoulder. This involves applying pressure downwards and sideways on the mother’s lower abdomen depending upon the position of the baby.
If these maneuvers fail to deliver the baby, the doctor may move to Second-Line Maneuvers. This might include trying to deliver the baby’s other arm first or using rotational maneuvers to reposition the baby. Another option could be the Gaskin maneuver, where the mother is put on her hands and knees to aid delivery (only for those without an epidural). Episiotomy (making an incision in the perineum) could be considered too, but this is generally not recommended in all cases as it doesn’t relieve obstruction caused by the baby’s shoulder.
In severe cases, the doctor may need to resort to extraordinary measures. These are only used when first and second-line maneuvers have failed and they can carry a higher risk to the baby and the mother. Specific maneuvers include intentionally fracturing the baby’s clavicle to decrease shoulder width, pushing the baby’s head back into the uterus for an emergency C-section (Zavanelli maneuver), or manipulating the baby’s shoulder through a surgical cut in the abdomen. In extreme cases where no other options are available, a symphysiotomy may be performed, which involves splitting the pubic bone to create room for the baby to pass.
It’s crucial that times and sequence of events are carefully documented during the delivery process. This can be beneficial for future healthcare providers to understand what happened during the delivery, as well as for advising patients on risks in subsequent pregnancies.
What else can Shoulder Dystocia be?
When a baby’s head seems to be pulling back during birth (known as the “turtle sign”), doctors need to consider a few possible medical issues. These may include a tight cord around the baby’s neck (nuchal cord), the baby being in an abnormal position, or it might be a completely normal part of the delivery process.
A quick check for a nuchal cord can be done after the baby’s head is delivered, and again when trying to deliver the baby’s shoulder. This will help the doctors clarify the situation.
What to expect with Shoulder Dystocia
Should a shoulder dystocia – a childbirth complication where the baby’s shoulder gets stuck behind the mother’s pelvic bone – be resolved, the future health of both the mother and the baby will depend on any complications that might have occurred. The mother might face health problems due to injuries during childbirth, such as bladder laceration or damage to the muscles controlling bowel movements, which may lead to long-term conditions like fecal incontinence, or loss of bowel control.
The baby might encounter injuries to the humerus or clavicle (the arm and collar bone, respectively) and the brachial plexus – a network of nerves extending from the spine to the shoulder, arm, and hand. These injuries often recover fully without causing permanent disabilities, but in roughly 10% of cases, they may lead to enduring nerve damage. However, training based on simulations has helped to lower the overall rate of complications related to shoulder dystocia.
There’s a minimum 10% chance that shoulder dystocia might reoccur in future pregnancies. It’s important to discuss the mother’s full health profile and potential risk factors with her when planning future pregnancies. Both the pros and cons of cesarean delivery – a surgical procedure to deliver the baby – should also be talked about since it’s the only assured way to avoid repeated shoulder dystocia.
According to the American College of Obstetricians and Gynecologists (ACOG), cesarean delivery shouldn’t be suggested to all women who’ve faced shoulder dystocia before, as the complication often does not happen again. The mode of delivery in future pregnancies should be decided keeping in mind the clinical factors and the mother’s personal choices.
Possible Complications When Diagnosed with Shoulder Dystocia
Shoulder dystocia during childbirth can lead to complications for both the mother and the baby. For the mother, these complications can happen more often when intense procedures to resolve the dystocia are required. These complications can include:
- Bleeding after giving birth
- Tears and injuries to the urinary tract, bladder, and the area around the vagina and rectum, potentially leading to problems with urinary and bowel control
- Nerve damage in the thigh from being in a specific position for a long time
- Separation of the pelvic joints due to excessive bending of the maternal legs
- Rupture of the uterus
The baby may also face various complications from shoulder dystocia. These complications include injuries from trauma during delivery, lack of oxygen, and even death. Traumatic injuries could be damage to the nerves in the baby’s arm or fractures of the collarbone or arm bones. These injuries occur in about 5.2% of births involving shoulder dystocia. The nerve damage could affect the upper nerves (Erb palsy), the lower nerves (Klumpke palsy), or the total nerve network in the arm. Moreover, a condition affecting the eye and eyelid called Horner syndrome as well as facial nerve damage could accompany the arm nerve injuries. Collarbone fractures and damage to the upper arm nerves are very common. However, the prognosis varies greatly, with the best outcome for upper nerve damage, while total arm nerve damage has the worst prognosis. In about 20% of these cases, the nerve injuries get better on their own, but around 10% of babies have long-lasting deficits.
Severe complications such as asphyxia, brain damage due to lack of oxygen (hypoxic encephalopathy), and even death are less frequent. However, they tend to occur after a long period between the delivery of the baby’s head and body, or after multiple maneuvers to resolve the dystocia. These complications are less common when the dystocia is resolved after the first maneuver. It’s also important to note that the length of time between the delivery of the head and the body doesn’t necessarily predict how severe the baby’s injuries will be, as cases of neonatal death have occurred even after relatively short intervals.
Preventing Shoulder Dystocia
Shoulder Dystocia is a situation during childbirth where the baby’s shoulder gets stuck after the head is delivered. There are certain methods doctors use to help prevent this problem. One of them is something called the McRoberts maneuver or applying pressure just above the pubic area before the baby’s head comes out. This can be done especially when there’s an increased likelihood of shoulder dystocia occurring, like when the baby is larger than usual or if the mother has diabetes. However, the usefulness of this tactic is still being explored as there are insufficient data to favor or go against it.
Other strategies include inducing labor early or planning for a cesarean section which is a surgical procedure to deliver the baby. The goal is to avoid the occurrence of shoulder dystocia in patients who are at high risk. At present, there is no clear evidence to show that these measures offer definite benefits. For most patients, these steps could result in increased costs and rates of cesarean sections.
In cases where diabetic patients are expected to deliver a baby weighing more than 4,500 grams or non-diabetic patients with a baby weighing more than 5,000 grams, a planned cesarean section might be considered. This suggestion is based on the increased possibility of detecting large-sized babies (pathologic fetal overgrowth). However, inducing labor early, regardless of the time along in the pregnancy, is not typically suggested because there isn’t enough evidence to support it.
Patients need to be aware of the risk factors for shoulder dystocia. It is important to maintain good blood sugar control during pregnancy, as well as maintaining a healthy weight gain, particularly in patients with gestational diabetes and obesity. For women who have previously encountered problems with shoulder dystocia, it’s critical to know that the chances of it happening again in any future vaginal deliveries are significantly higher.
