One of the more rare complications of labor and delivery is shoulder dystocia. What is shoulder dystocia? It is a complication that occurs then the baby’s head is delivered but his or her shoulders become stuck behind the mother’s pubic bone. This makes continuing with delivery very difficult.
According to Dr. G. Thomas Ruiz,
“It’s very dangerous depending on how stuck that shoulder is. So if you don’t get delivery done in a quick enough fashion, the baby can actually suffer a lack of oxygen to the brain.”
Fortunately, shoulder dystocia is considered a rare complication. In 2016, a study in the Women’s Health journal estimated that only 0.15% to 2% of births involve shoulder dystocia. However, there is no way to tell for sure if you will experience this complication. There is also no surefire way to prevent it. The best thing you can do is understand the complication and risk factors, and talk to your doctor about the risks.
What are the Risk Factors for Shoulder Dystocia?
While there is no surefire way to prevent shoulder dystocia, there are some things that can be done to avoid it. Primarily, healthcare providers must understand which patients are at an increased risk of this happening. Healthcare providers can best determine who is at risk by considering the following:
- History of shoulder dystocia in previous pregnancies
- Maternal obesity
- Maternal diabetes
- Gestational diabetes
- Excessive weight gain during pregnancy
- Macrosomia (infant who is large for gestational age)
- Post-term pregnancy
- Estimated fetal weight is concerning for cephalopelvic disorder (CPD)
- Protracted active dilation
- Dilation that stops
- Prolonged deceleration
- Failed or protracted fetal descent
- Long second stage of delivery
- Instrumental delivery
By considering these risk factors, healthcare providers can plan accordingly during pregnancy, labor and delivery. For example, women with diabetes may benefit from a scheduled Cesarean section (c-section), rather than attempting a natural birth.
Also, during prenatal care, healthcare providers can use cephalopelvimetry to identify physical risk factors. Certain pelvic features may predispose certain women to the risk of shoulder dystocia. More specifically, women with a narrow pelvic or pubic structure are at a higher risk of the infant becoming stuck. This is especially true if the infant is large for his or her gestational age or in a post-term delivery.
Research notes that predicting shoulder dystocia is almost impossible. However, healthcare providers can reduce the risk by recognizing risk factors and taking measures early on during pregnancy and labor. For example, sonography can be used to determine the baby’s size and weight. Also, doctors can estimate the level of risk by addressing the type and number of risk factors present.
How do Doctors Correct Shoulder Dystocia?
When a baby becomes stuck in the birth canal, there is a risk of oxygen deprivation. Therefore, the doctor who is delivering the baby must make a choice as to how to proceed. Some of the options for delivering an infant who is stuck behind the pubic bone include:
- Episiotomy – The doctor makes an incision in the vaginal opening to provide more room for the baby to be delivered.
- Suprapubic Pressure Maneuver – A doctor or nurse applies external pressure to the pubic bone. This is done to attempt to dislodge the shoulder that is stuck.
- Corkscrew Maneuver – The doctor attempts to rotate the baby’s position to dislodge the shoulder. This maneuver is done through the vaginal opening.
- McRobert’s Maneuver – Two nurses or assistants take hold of each maternal leg and flex the thighs back against the abdomen. This is done to help release the shoulder that is stuck.
- Zavanelli Maneuver – When natural birth attempts fail, this maneuver involves pushing the baby back into the uterus then performing an emergency c-section.
Sadly, some of these options involve quite a bit of force and can result in birth injuries, including nerve damage, paralysis, brain damage and physical trauma. Some of these methods can also cause injuries to the mother. Mothers may experience pelvic floor damage, tears through the vagina and/or rectum and hemorrhaging.
What are the Risks of Shoulder Dystocia for Infants?
The primary risk of shoulder dystocia for infants is oxygen deprivation, which can lead to brain damage and a host of medical problems. But that is not the only injury that infants may experience. Other possible injuries include:
- Brain Damage – Lack of oxygen at birth can cause brain damage, such as hypoxia or anoxia, or can even be fatal. Infants who are deprived of oxygen may develop disabilities like cerebral palsy, attention deficit hyperactivity disorder (ADHD), seizure disorders and autism. Depending on the severity of the brain damage, the consequences can be long-term.
- Brachial Plexus Injury – Shoulder dystocia is the primary cause of brachial plexus injuries. Brachial plexus injuries occur in 1-20% of infants with shoulder dystocia. This injury causes damage to the nerves that connect the hand, arm and shoulder to the spinal cord. Most brachial plexus injuries heal without causing permanent damage. Sometimes, however, the nerves are stretched to the point that they cannot heal.
- Bone Fractures – When force is applied during delivery with shoulder dystocia, the infant may experience fractures or broken bones in the arm or collarbone (clavicle). Generally, fractures heal well and the infant does not have permanent damage.
In order to minimize the risk of birth injuries due to shoulder dystocia, healthcare providers must act with deliberate, urgent and logical steps. The delivery room team must work together to ensure the best outcome possible for the mother and infant.