What is Shoulder Dystocia?
When you’re preparing for the birth of your baby, you may consider all of the ways in which you’d like to manage labor: what pain medications you plan to use, which comfort measures might help instead of medications, how you’d like to move around during labor, and more. What you might not be planning for is baby getting stuck in your pelvis during the birth process — though many expectant parents fear this happening.
Shoulder dystocia is the term used when the delivery of baby’s shoulders is impeded by mom’s pelvic anatomy. Baby’s head and first shoulder may be delivered, and then the second shoulder gets stuck on mom’s symphysis pubis (pubic bone) or on her sacral promontory (tail bone). This sometimes happens if baby is large, or if baby’s rotation is incomplete, though many times no reason can be attributed as the main cause. Shoulder dystocia occurs in 0.2% to 3% of vaginal deliveries when the baby is in vertex presentation (head down).
Once shoulder dystocia is identified, care providers need to intervene quickly to keep baby from experiencing negative health effects.
Can shoulder dystocia be prevented?
Some maternal and fetal factors can increase the risk of shoulder dystocia, though shoulder dystocia does not always occur for moms or babies with these conditions:
- A suspected large baby (fetal macrosomia): Nearly half of the cases of shoulder dystocia are a result of a large baby; however, most large babies (70% to 90%) are delivered without incident. The inaccuracy of predicting fetal size late in pregnancy also makes this a less-than-ideal marker for risk of this complication.
- A baby born after his due date: Post-term babies tend to be bigger, thus the greater risk of getting stuck.
- Labor induction: If labor is forced to begin before the mother’s or baby’s body is prepared, the likelihood of labor dysfunction is increased.
- Maternal diabetes mellitus: This increases the risk of shoulder dystocia by more than 70%, mainly because babies of diabetic mothers are larger. It may not be the birthweight, but rather the differences in growth for these babies (larger shoulder and extremity circumferences, more body fat, and thicker upper extremity skinfolds, for example).
- Assisted vaginal delivery: When a vacuum extractor or forceps are needed for delivery, the risk of shoulder dystocia increases by 35% to 45%.
- Labor dysfunction: If labor does not progress as expected, or if the active stage of labor is exceptionally long, shoulder dystocia risk increases.
- Previous shoulder dystocia: Depending on the study, recurrence rates are between 1% and 17%.
Having a combination of risk factors above makes shoulder dystocia more likely, though one study concluded:
“Only 25% of all shoulder dystocia cases had one or more significant risk factors.”
The American College of Obstetricians and Gynecologists (ACOG) agrees that shoulder dystocia is difficult to predict accurately. They caution that even though there are risk factors, practitioners should be ready for shoulder dystocia in all deliveries.
Controversy exists surround whether or not cesarean birth should be routinely recommended in the case of multiple risk factors for shoulder dystocia. While cesarean birth may eliminate a small number of cases of shoulder dystocia, the increase in cesarean surgeries would increase healthcare costs and maternal morbidity disproportionately, thus it may not be the best solution.
See also: C-Sections: Everything You Need to Know
What happens when a baby gets stuck during delivery?
If during labor your birth attendant identifies shoulder dystocia, a series of interventions can be attempted to deliver the baby quickly and limit any damage to mom or baby. If the baby cannot be delivered with increased gentle traction, these additional interventions may include:
- McRoberts maneuver: The mother’s legs will be sharply bent toward her chest in an effort to change the shape of the pelvis, increasing the pelvic outlet, and freeing baby’s shoulder from the pubic bone.
- Suprapubic pressure: Pressure will be applied to the mother’s abdomen, which may help rotate and push the trapped shoulder underneath the pubic bone.
- Roll the patient: Changing from a recumbent position to a hands-and-knees position often frees a trapped shoulder by changing the pelvic dimensions and allowing movement of mom’s tailbone.
- Woods/Rubens maneuver: These movements require the doctor to place his hands into the birth canal to physically rotate the baby and extricate the trapped shoulder.
- Episiotomy: This is an incision from the vaginal opening toward the anus. The theory is that this will increase the amount of room for delivery, though the problem is not typically with the soft tissue. The ACOG does not recommend routine episiotomy in all cases of shoulder dystocia but suggests conservative use on an as-needed basis. If a vacuum extractor or forceps have been attempted to aid in delivery, the episiotomy may have been cut then.
- Zavenelli maneuver: Rarely, the doctor will push the baby back into the vagina and then perform a cesarean surgery for delivery.
- Symphyiotomy: Rarely used, this is a surgical cut to the mother’s pubic bone to free baby’s body.
When an increased number of maneuvers are needed to deliver the baby, the risk of injury is increased. In addition, births managed with just fetal maneuvers are less likely to cause injury compared to birth with maternal maneuvers.
See also: Episiotomies: Healing and Complications
Possible Infant Complications
The main risk to the baby is lack of oxygen as the umbilical cord is compressed between baby’s body and the cervix during contractions, which is why interventions to deliver the baby take place very quickly once shoulder dystocia is identified. Other infant injuries include:
- Clavicle or humerus fractures, which typically resolve without lasting damage, are the most common fetal injury associated with shoulder dystocia.
- Brachial plexus injury (including Erb’s palsy, Klumpke’s palsy, etc.) occurs in 10% to 20% of shoulder dystocia cases. This damage to the nerves of the shoulder, arm, or hand may be transient or permanent.
- Hypoxia (which may result in permanent brain damage) occurs in fewer than 1% of births associated with shoulder dystocia.
In very rare instances, an infant may die due to shoulder dystocia, though in some of these cases other types of fetal compromise (such as abnormal heart rate during labor or presence of meconium in the amniotic fluid) were identified before birth.
See also: Baby’s Heart Rate: What it Means for Brain Injuries
Possible Maternal Complications
Maternal injuries as a direct result of shoulder dystocia include:
- Third- and fourth-degree lacerations due to episiotomy or a natural tear that extends into the anus or rectum.
- Postpartum hemorrhage, which is abnormally heavy bleeding. This is reported in 11% of cases.
- Symphyseal separation, a dislocation of the pubic bone which may involve transient or permanent nerve damage to the leg, can occur when a mother’s legs are aggressively flexed, especially if mom has an epidural and cannot feel pain from the abnormal movement.
- Uterine rupture, urethral injury, and bladder lacerations are rare but possible complications.
How is shoulder dystocia treated?
If your baby experiences shoulder dystocia during the birth process, the treatment will depend on the type and severity of injuries that occur, as well as whether they occur to you or to your baby.
In most cases, the baby is delivered without any type of injury, and only observation is recommended. Other times, you or your baby may require physical therapy or, in the worst case, surgery. Early treatment has the most likely chance of improving function so that you or your baby do not suffer long-lasting repercussions of shoulder dystocia.
If you or your baby’s injuries were caused by a medical team error, it’s important to know that you have legal options. You don’t have to deal with the pain — or the cost of that pain — alone. Contact Safe Birth Project today to see how we can help.
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