Shoulder Dystocia

Shoulder dystocia

definition

• a vaginal cephalic delivery that requires additional obstetric manoeuvres to deliver the fetus after the head has delivered and gentle traction has failed.

pathophysiology

• It occurs when the anterior shoulder becomes impacted against the symphysis pubis or the posterior shoulder becomes impacted against the sacral promontory. Anterior impaction tends to be more common, but infrequently, both anterior and posterior impaction can occur.

Risk factorsAntenatal• Post-term pregnancy• High parity• Previous history of shoulder dystocia• Previous large babies Maternal obesity (weight > 90kgs at delivery)• Maternal age over 35 years• Maternal diabetes and gestational diabetes• Excessive weight gain in pregnancy• Clinically large baby/symphysis-fundal height measurement larger than dates• Fetal growth > 90th centile on ultrasound scan (fetal macrosomia)Intrapartum• Birthing in a semi-recumbent position on a bed can restrict movement of the sacrum and

coccyx (McGeown 2001)• Prolonged labour, notably protracted late first stage (usually between 7–10cm) with a

cervix that is loosely applied to the presenting part• Oxytocin augmentation• Prolonged second stage• Mid-pelvic instrumental delivery http://www.midirs.org/development/studentmidwife.nsf/B2F0D90AEC3F15BF8025764A00462EB9/$File/Shoulder%20Dystocia.pdf

Factors associated with shoulder dystocia

Pre-labour • Previous shoulder dystocia • Macrosomia >4.5kg • Diabetes mellitus • Maternal body mass index >30kg/m2• Induction of labour Intrapartum• Prolonged first stage of labour• Secondary arrest• Prolonged second stage of labour• Oxytocin augmentation• Assisted vaginal deliverRCOG 2012 http://www.rcog.org.uk/files/rcog-corp/GTG%2042_Shoulder%20dystocia%202nd%20edition%202012.pdf

Maternal complications:• Postpartum haemorrhage (approximately two-thirds

will have a blood loss >1000 ml) (Benedetti & Gabbe 1978)

• Soft tissue trauma• Third or fourth degree perineal tears (extension of

episiotomy)Fetal and neonatal complications:• Fetal hypoxia or neonatal asphyxia – potential for

neurological damage• Brachial plexus injury – Erb’s Palsy/Klumpke’s paralysis

(Tiran 2003)• Fractures to the clavicle or humerus• Intrapartum fetal deathhttp://www.midirs.org/development/studentmidwife.nsf/B2F0D90AEC3F15BF8025764A00462EB9/$File/Shoulder%20Dystocia.pdf

• H• E• L

• P• E

• R• R

• Call for help• Evaluate for episiotomy• Legs (the McRobert’s

manoeuvre)• Suprapubic pressure• Enter manoeuvres (internal

rotation)• Remove the posterior arm• Roll the woman/rotate

onto ‘all fours’

Documentation

• Time of birth of the head• Direction baby facing• Procedures required to birth the shoulders

and length of time of each procedure• Time of delivery• Staff in attendance• Condition of baby and resuscitation required • Baby’s weight

The McRoberts' manoeuvre

Suprapubic pressure

Delivery of the posterior arm

Timely management of shoulder dystocia requires prompt recognition. The attendant health carer should routinely observe for:

● difficulty with delivery of the face and chin● the head remaining tightly applied to the vulva or even retracting (turtle-neck sign)● failure of restitution of the fetal head● failure of the shoulders to descend.

ManagementRationales

Managed systematically (HELPERRD) Improved perinatal outcomes

Call for help, state problem clearly Time is essential. Up to five minutes, otherwise high risk of fetal hypoxic ischaemic injury. Additional midwife, obstetrician, neonatal resuscitation team, anaesthetist.

Discourage maternal pushing May exacerbate impaction of the shoulders.

McRoberts’ manoeuvre : the woman lie flat with pillows removed from under her back. Legs hyperflexed. Position the maternal thighs on her abdomen.

Flexion and abduction of the maternal hips. It straightens the lumbosacral angle, rotates the maternal pelvis towards the mother’s head and increases the relative anterior-posterior diameter of the pelvis.

Apply suprapubic pressure from the side of the fetal back in a downward and lateral direction just above the symphysis pubis, pushing the anterior shoulder towards the fetal chest for around 30 seconds.

It reduces the fetal bisacromial diameter and rotates the anterior fetal shoulder into the wider oblique pelvic diameter. The shoulder is then freed to slip underneath the symphysis pubis with the aid of routine axial traction.

episiotomy Allow the more space to facilitate internal vaginal manoeuvres.

Wood manoeuvre: press on the anterior or posterior aspect of the posterior shoulder.

Pressure on the posterior shoulder to the chest can reduce the shoulder diameter by adducting the shoulder. It also rotates the shoulder into the wider oblique diameter.

Rubin manoeuvre: apply pressure on the anterior shoulder Adduct and rotate the anterior shoulder into the oblique diameter

Deliver the posterior arm : the fetal wrist should be grasped and the posterior arm should be gently withdrawn from the vagina in a straight line.

Reduce the diameter of the fetal shoulders by the width of the arm. Humeral fractures

Primary postpartum haemorraghe

• Blood loss from the vaginal in excess of 500 ml and occurring within 24 hours of delivery.

Four ‘T’s• Tone – atonic uterusAnaemiaMultiple pregnancyPolyhydramniosMacrosomiaMaternal obesityGrand multiparityAPH placenta praeviaFibroidsPrecipitate/prolonged labourInduced labour/ augmented labourFull bladderCaesarean sectionUterine abnormalities

Previous PPH• Tissue – incomplete placental

separation, retained productsMismanagement of third stage• Trauma – lacerations to the genital tractUterus, vagina, perineum, labia, cervixOperative birth• Thrombin – blood coagulation disorderSevere preeclampsiaAntepartum haemorrhageAmniotic fluid embolusIntrauterine deathSepsisExisting clotting disorders

First-line drug therapy

• Syntometrine (oxytocin 5 unit and ergometrine 0.5 mg) IM

• Syntocinon 5 unit IV• Syntocinon 40 unit in 1 L Hartmann’s solution

at 250 ml/hour IV infusion• Ergometrine 0.25 mg IM

Cord prolapse

• Descent of the umbilical cord through the cervix alongside or past the presenting part with ruptured membranes.

Risk factors• General Low birth weight < 2.5 kgPrematurity < 37 weeksPolyhydramniosMalpresentation (breech presentation, transverse lie)High presenting partFetal congenital anomaliesMultiparitySecond twin

• Procedure relatedArtificial rupture membranesExternal cephalic versionInternal podalic versionStabilising induction of labourApplying fetal scalp electrodeRotational instrumental delivery

• Recognise • Call for help• Relieve cord compressionKnee-chest position or Left-lateral with a pillow under left hipElevate the presenting part Stop oxytocin if is in progressGently handle and replace the cord back into the vagina• Continuous EFM• Assessment for delivery