Shoulder Dystocia

Definition

-Impaction of anterior shoulder of fetus against symphysis pubis after fetal head has been delivered

-Life threatening emergency

Etiology epidemiology

-Incidence 0.15-1.4% of deliveries

-Occurs when breadth of shoulder is greater than biparietal diameter of the head

Risk factor

-Maternal: obesity, Diabetes, multiparity

-Fetal: prolonged gestation, macrosomia

Labour :

-Prolong 2^nd stage

-Prolonged deceleration phase (8-10 cm)

-Instrumental midpelvic delivery

Clinical feature

-“Turtle sign” (head delivered but retracts against inferior portion of pubic symphysis)

Complications:

Chest Compression by vagina or cord compression by pelvis can lead to hypoxia

Danger of brachial plexus injury (Erb palsy: C5-C7.klumpke;s palsy: C8-TI )

-90% resolve within 6 months

Fetal fracture (clavicle, humerus, cervical spine )

Maternal perineal injury, may result in PPH

Intrapartum fetal hypoxia of trauma

Treatment

Goal: to displace anterior shoulder from behind symphysis pubis; follow a stepwise approach of maneuvers until goal achieve (see box)

Other option when ALARMER fails :

-Cleidotomy (deliberate fracture of neonatal clavicle)

-Zavanelli maneuver: replacement of fetus into uterine cavity and emergent C/S

-Symphysiotomy

-Abdominal incision and shoulder disimpaction via hysterotomy - Subsequent vaginal delivery 

Prognosis

-90%of shoulder dystocias will resolve with McRobert’s maneuver and suprapubic pressure

-1%risk of long term disability for infant.