Shoulder dystocia occurs when the baby's head has delivered, but the anterior shoulder becomes impacted behind the mother's pubic symphysis. This obstetric emergency happens because the bisacromial diameter of the fetus fails to pass through the anteroposterior diameter of the pelvic outlet. In a normal delivery, the shoulders rotate into an oblique diameter of the pelvis, allowing them to slip past the bony pelvis without obstruction. When this mechanism fails, the normal downward traction of the midwife will only wedge the shoulder tighter against the maternal bone. Midwives working in primary health centres across Nigeria must remember that standard downward pulling during shoulder dystocia is dangerous and must be avoided completely.
While shoulder dystocia can strike unexpectedly in low-risk pregnancies, several predisposing factors raise clinical suspicion. Antenatal risks include fetal macrosomia, maternal diabetes mellitus, post-term pregnancy, and a previous history of shoulder dystocia. Intrapartum red flags involve a prolonged first stage of labor, secondary arrest of descent, and a protracted second stage requiring operative vaginal delivery with forceps or vacuum. Many cases occur without any identifiable warning signs, meaning every birth attendant must remain constantly vigilant during the second stage of labor.
Recognizing shoulder dystocia instantly is the first step toward saving the baby. The cardinal sign is the turtle sign, where the baby's head delivers but then retracts tightly back against the perineum, much like a turtle pulling its head into its shell. Other clear indicators include the failure of the restitution mechanism, where the delivered head fails to turn spontaneously to align with the shoulders, and the failure of the shoulders to descend down the birth canal despite maternal pushing and primary maneuvers.
When shoulder dystocia is diagnosed, time is critical because umbilical cord compression cuts off the baby's oxygen supply.
The HELPERR mnemonic guides systematic management of shoulder dystocia.
Shoulder dystocia carries severe risks for both mother and baby.
| Recipient | Common Complications |
|---|---|
| Maternal | Postpartum hemorrhage, severe perineal lacerations (third and fourth degree), uterine rupture, symphyseal separation |
| Neonatal | Brachial plexus injury (Erb's palsy), clavicle fracture, humeral fracture, hypoxic-ischemic encephalopathy, neonatal death |
Prompt resolution minimizes long-term disability, but delayed maneuvers increase the likelihood of permanent nerve damage.
Once the baby is delivered, immediate newborn resuscitation must proceed alongside maternal stabilization. Midwives must assess the infant for respiratory effort, tone, and signs of skeletal or nerve injury. On the maternal side, check for heavy bleeding and repair any genital tract trauma. Detailed documentation is vital for clinical continuity and legal protection. The record must include the exact time of head delivery, the maneuvers attempted, the order in which they were performed, the duration of the dystocia, and the condition of both mother and baby at birth.