Shoulder dystocia, a serious childbirth complication, occurs when, after the baby’s head emerges, the baby’s shoulders become lodged behind the mother’s pubic bone or sacrum. Understanding this event is important for expectant parents, especially when considering subsequent deliveries.
What Is Shoulder Dystocia?
Shoulder dystocia is defined as a vaginal delivery where the baby’s head has been born, but the shoulders fail to follow with gentle traction. This occurs when the anterior shoulder gets stuck behind the mother’s pubic bone, or less commonly, the posterior shoulder becomes lodged against the sacrum. A delay in delivery of the shoulders can lead to a reduction in oxygen to the baby. It is considered an obstetric emergency, requiring immediate intervention from the medical team.
A key indicator of shoulder dystocia is the “turtle sign,” where the baby’s head emerges but then retracts back against the mother’s perineum. The main concern during this event is the potential for umbilical cord compression and oxygen deprivation to the baby.
Recurrence Risk and Contributing Factors
A previous history of shoulder dystocia is the most significant factor increasing the likelihood of it happening again in a subsequent delivery. While the overall incidence of shoulder dystocia in vaginal births is relatively low, ranging from 0.2% to 3%, the risk of recurrence is considerably higher. Studies indicate recurrence rates can be between 6% and 25%, with some reports suggesting an average of about 7.2%, which is significantly elevated compared to the general population.
Several factors contribute to this increased recurrence risk. Maternal factors include gestational diabetes, which can lead to larger babies, and excessive weight gain during pregnancy. Maternal height, particularly shorter stature, has also been identified as a risk factor for recurrence.
Fetal characteristics also play a role, primarily large fetal size, known as macrosomia, typically defined as a birth weight over 8 pounds, 13 ounces. Babies born to mothers with diabetes are at a higher risk, even at lower weights, due to differences in body composition where they may have larger shoulders relative to their heads. If a baby’s birth weight is greater than in the previous delivery, this further increases the chance of recurrence.
Certain aspects of the labor and delivery process can also influence the risk. These include a prolonged second stage of labor or the need for an operative vaginal delivery in the previous birth, such as with forceps or a vacuum device.
Planning for Subsequent Deliveries
When planning a subsequent pregnancy and delivery after a previous shoulder dystocia, consulting with an obstetrician or a high-risk pregnancy specialist is an important first step. This allows healthcare providers to assess individual risk based on the specific circumstances of the prior event and current health to develop a personalized care plan.
Healthcare providers will conduct a thorough risk assessment, which may involve monitoring fetal growth more closely with ultrasounds in later pregnancy. This helps estimate the baby’s size and identify any potential for macrosomia. Discussions about birth options will occur, including the possibility of a trial of labor with specific precautions or a planned Cesarean section (C-section).
A planned C-section may be considered if the estimated risk of recurrence is high, offering a way to avoid the complication. Many women can still have a vaginal birth with careful management. Lifestyle adjustments, such as managing gestational diabetes or maintaining a healthy weight before and during pregnancy, can also contribute to reducing the overall risk in future deliveries.
Navigating Labor and Delivery
For deliveries where shoulder dystocia is anticipated due to a prior history, medical teams prepare proactively. This often includes having additional staff, such as experienced obstetricians, midwives, and a neonatal team, ready in the delivery room. Enhanced monitoring during labor helps to identify any signs that might suggest a higher risk of the complication.
If shoulder dystocia occurs, the medical team will immediately initiate specific maneuvers to release the baby’s shoulders. The McRoberts maneuver is often the first technique employed, involving hyperflexing the mother’s legs towards her abdomen to widen the pelvis. This may be combined with suprapubic pressure, where an assistant applies pressure just above the pubic bone to help dislodge the anterior shoulder.
Other maneuvers include the Gaskin maneuver, which involves repositioning the mother onto her hands and knees to change the pelvic dimensions. Rotational maneuvers, such as the Rubin or Woods screw maneuvers, involve internal rotation of the baby to free the impacted shoulder. These techniques are performed by trained professionals to safely deliver the baby while minimizing potential injury.
Following a shoulder dystocia event, immediate care focuses on assessing both the mother and baby for any potential injuries. The medical team will check the baby for issues like nerve damage or fractures. The mother will also be assessed for any tears or excessive bleeding.