Shoulder dystocia is defined as a complication at birth that requires additional obstetric maneuvers for the baby’s shoulders to protrude, having become embedded in the pelvic cavity after the head has emerged.
According to WHO data, its incidence is estimated to be 0.6-1.4% in babies weighing between two and a half kilos and four kilos, and 5% -9% in babies weighing more than four kilos.
We will tell you why shoulder dystocia occurs and what consequences it can have for the baby and the mother if it is not managed correctly and on time.
What is Shoulder Dystocia
Shoulder dystocia occurs when the baby’s shoulder becomes locked behind the maternal pelvis after the head is released. It is considered one of the high-risk situations in obstetrics and can cause significant complications if not handled correctly.
It is an unpredictable situation, but there are certain risk factors that must be taken into account when attending the delivery, as they could increase the chances of the baby suffering from shoulder dystocia:
Although the weight of the baby is a factor associated with this pathology, 50% of shoulder dystocia occur in neonates weighing less than 4 kg, making it very difficult to prevent this serious complication.
- Macrosomic Babies
- Those born to diabetic mothers have a risk of up to four times higher compared to children of the same weight born to non-diabetic mothers
- History of shoulder dystocia (recurrence up to 25%)
- Chronologically prolonged gestation
- Excessive weight gain during pregnancy (more than 20 kg)
- Maternal obesity
- The pelvic dimension of the mother too narrow
- Alterations in labor and instrumental delivery
Shoulder Dystocia Prevention
As we have just mentioned, shoulder dystocia cannot be prevented, although as we read in the action protocol prepared by the Sant Joan de Deu Hospital and the Barcelona Clinic, the following recommendations should be followed to try to minimize the risks:
- Control the weight that the mother gains during pregnancy
- Women diagnosed with gestational diabetes should have proper medical follow-up
- Offer the option of performing an elective cesarean section in the event that the baby is estimated to weigh more than 5 kilos or 4.5 kilos in diabetic mothers
- In the case of mothers who have had previous deliveries with shoulder dystocia, the method of delivery should be agreed upon and attended by specialists in maternal-fetal medicine.
Complications of Shoulder Dystocia
Among the maternal complications associated with shoulder dystocia are:
- IV degree perineal tears (3.8%)
- Uterine atony
- Vaginal bruising
- Uterine rupture and postpartum hemorrhage (11%)
- Post-traumatic stress syndrome
- Interaction problems between mother and baby
With regard to the baby, the consequences of shoulder dystocia not resolved in time can be very serious, presenting:
- Different levels of suffocation
- Transient (3.3-16.8%) or permanent (0.5-1.6%) brachial plexus injuries
- Clavicle fracture (1.7-9.5%)
- Humerus fracture (0.4-4.2%)
- Encephalopathy and other derivatives of feto-neonatal hypoxia
- Neonatal death
Shoulder Dystocia Treatment
As we have seen, shoulder dystocia is an obstetric emergency that requires great knowledge, dexterity, and speed of action from the professionals who attend childbirth. Since it is difficult to foresee a situation, it is important that doctors know how to identify it and treat it correctly when it occurs.
Thus, in the event of shoulder dystocia, WHO recommends:
- Help the woman to flex her legs and bring them to her chest, as close as possible (McRobert maneuver). This posture frees the sacrum and increases the diameter of the pelvic area, and helps to solve 90% of cases
- Apply firm and continuous downward traction on the fetal head to move the anterior shoulder below the symphysis pubis. In no case should excessive traction be carried out on the head, as this practice could cause an injury to the brachial plexus.
- Apply suprapubic pressure in order to disengage the shoulder and penetrate the pelvis. By itself, this maneuver helps resolve 42% to 80% of shoulder dystocia, but combined with the McRoberts maneuver, the success rate is significantly increased.
If despite these practices, the baby’s shoulder still does not come out, other exceptional and invasive measures would have to be carried out, which are published in the WHO document cited above.
The important thing, in any case, is that the moment shoulder dystocia is detected, the professionals who care for the mother know how to act calmly but without time to lose.