Intrapartum Care: Umbilical Cord Prolapse, Shoulder Dystocia & Instrumental Delivery Flashcards
What is cord prolapse?
When the umbilical cord descends below the presenting part of the fetus and through the cervix into the vagina, after rupture of the fetal membranes.
If left untreated, what can umbilical prolapse lead to?
Compression of the cord or cord spasm –> fetal hypoxia.
What is the most significant risk factor for cord prolapse?
When the fetus is in an abnormal lie after 37 weeks gestation (i.e. unstable, transverse or oblique).
How does the fetus being in an abnormal lie increase the risk of cord prolapse?
Being in an abnormal lie provides space for the cord to prolapse below the presenting part.
In a cephalic lie (normal), the head typically descends into the pelvis, without room for the cord to descend.
Risk factors for cord prolapse?
- abnormal presentations e.g. Breech, transverse lie
- prematurity
- multiparity
- polyhydramnios
- twin pregnancy
- cephalopelvic disproportion
When do approx 50% of cord prolapses occur?
At artificial rupture of the membranes.
When should cord prolapse be suspected?
Where there are signs of fetal distress on the CTG.
How is a diagnosis of cord prolapse made?
Signs of fetal distress on the CTG + cord palpable on vaginal exam.
Management of cord prolapse?
Obstetric emergency!
1) The presenting part of the fetus may be pushed back into the uterus to avoid compression
2) If the cord is past the level of the introitus, there should be minimal handling and it should be kept warm and moist to avoid vasospasm
3) C section usually indicated
In cord prolapse, if the cord is past the level of the introitus, how can vasopasm be avoided?
1) minimal handling of cord
2) keep cord warm and moist
In cord prolapse, what position should the woman be in until preparations for an immediate caesarian section have been carried out?
Patient is asked to go on ‘all fours’.
The left left lateral position (with a pillow under the hip) is an alternative.
What drug can be used in cord prolapse to reduce uterine contractions whilst waiting for delivery by caesarean section?
Tocolytics e.g. nifedipine, terbutaline
Why can retrofilling the bladder with 500-700ml of saline be helpful in cord prolapse?
As it gently elevates the presenting part.
1st line of delivery in cord prolapse?
Caesarian section
Why is patient asked to go on all fours in cord prolapse?
This position uses gravity to draw the fetus away from the pelvis and reduce compression on the cord.
What is shoulder dystocia?
A complication of vaginal cephalic delivery when the anterior fetal shoulder becomes stuck on the maternal pubic symphysis, resulting in delayed birth of the baby’s body.
Obstetric emergency!
What is the major complications of shoulder dystocia?
1) Shoulder compression may cause the umbilical cord to become compressed between the baby’s body and the mother’s pelvis.
2) The baby’s neck may be compressed at an angle that limits blood flow.
3) Hypoxia brain injury due to interruption of the oxygen supply.
Cause of shoulder dystocia?
Shoulder dystocia usually occurs unexpectedly during childbirth and is not predictable.
What are some pre-labour risk factors for shoulder dystocia?
1) previous shoulder dystocia
2) macrosomia >4.5kg
3) diabetes mellitus
4) maternal BMI >30
5) induction of labour
What are some intrapartum risk factors for shoulder dystocia?
1) prolonged 1st stage of labour
2) 2ary arrest: no change in cervical dilation over time.
3) prolonged 2nd stage of labour
4) oxytocin augmentation
5) assisted vaginal delivery
How does a baby’s birth weight affect risk of shoulder dystocia?
Shoulder dystocia is more likely in babies with higher birth weights, but it should be noted that there is no difficulty delivering the shoulders in most babies over 4.5kg.
What is the biggest maternal risk factor for shoulder dystocia?
Diabetes: the risk is significantly higher, even with a similar-sized baby.
If a woman has pre-existing diabetes or develops diabetes in pregnancy, what will they be offered to reduce/eliminate risk of shoulder dystocia?
Early labour induction or planned caesarean.
How does shoulder dystocia present?
1) Difficulty delivering the face and head.
2) Unable to deliver the anterior shoulder after the delivery of the head with the next contraction
3) May be failure of restitution: where the head remains face downwards (occipito-anterior) and does not turn sideways as expected after delivery of the head.
4) The turtle-neck sign: where the head is delivered but then retracts back into the vagina.
What is the turtleneck sign?
The appearance and retraction of the baby’s head (like a turtle withdrawing into its shell), with a red, puffy face.
Management of shoulder dystocia?
1) Call for help
2) Advise the mother to stop pushing
3) 1st line: McRoberts manoeuvres
What is 1st line manoeuvre in shoulder dystocia?
McRoberts manoeuvres
Why is the mother advised to stop pushing in shoulder dystocia?
As can worsen the fetal impaction.
What is McRoberts manoeuvres?
1) Hyperflex & abduct maternal hips to widen the pelvic outlet i.e. bringing thighs towards abdomen (this alone has a success rate of about 90% which is even higher when combined with suprapubic pressure)
2) Suprapubic pressure applied behind the anterior shoulder to disimpact it from the maternal symphysis.
2nd line manoeuvres in shoulder dystocia if McRoberts manoeuvres is unsuccessful?
1) Posterior arm: inserting the hand posteriorly to grasp the posterior fetal arm and deliver
2) Internal rotation (‘corkscrew’): simultaneously applying pressure in front of one shoulder and behind the other. The aim is to rotate the baby 180 degrees.
What is an episiotomy?
An incision between the vagina and anus.
How can an episiotomy be used in shoulder dystocia?
An episiotomy can allow more space to facilitate internal vaginal manoeuvres but will not relieve the bony obstruction of the shoulder.
Why should you always avoid downwards traction on the fetal head in shoulder dystocia?
As this increases the risk of brachial plexus injury (a major cause of litigation in obstetrics).
Post-delivery management in shoulder dystocia?
1) Active management of the third stage of labour is recommended due to the increased risk of post-partum haemorrhage
2) Shoulder dystocia can be a traumatic experience for the mother and birth partner, provide support and debrief the following delivery
3) A rectal examination should be performed to exclude a third- or fourth-degree tear
4) Paediatric review is recommended before discharge to assess for complications such as brachial plexus injury
Is there risk of recurrence of shoulder dystocia in future pregnancies?
Yes - mothers should be informed of this risk and given options for subsequent deliveries.
maternal complications of shoulder dystocia?
1) Third- or fourth-degree tears
2) Post-partum haemorrhage
3) Trauma/post-traumatic stress disorder
Foetal complications of shoulder dystocia?
1) Brachial plexus injury (BPI)
2) Fractures: humerus or clavicle
3) Hypoxic brain injury.
What % of babies who have shoulder dystocia will have a degree of brachial plexus injury.
What is the most common type of injury?
Erb’s palsy.
This is usually temporary, and movement will return within hours or days. Permanent damage is rare.
What is a brachial plexus injury?
Stretching of the brachial nerve plexus in the neck.
What is Erb’s palsy?
A paralysis of the arm caused by injury to the upper trunk C5-C6 of the brachial plexus.
What is instrumental delivery/operative vaginal delivery (OVD)?
Instrumental delivery refers to a vagina delivery assisted by either a ventouse suction cup or forceps.
These tools are used to help deliver the baby’s head.
What % of births in the UK are assisted by an instrumental delivery?
Around 10%
What are the 2 main instruments used in operative deliveries?
1) ventouse
2) forceps
The choice is operator dependent, but forceps tend to have a lower risk of fetal complications, and a higher risk of maternal complications.
Risk of fetal and maternal complicatiosn when using forceps vs ventouse in birth?
Forceps –> lower risk of fetal complications but a higher risk of maternal complications.
Ventouse –> higher risk of fetal complications but a lower risk of maternal complications.
What is recommended after instrumental delivery to reduce the risk of maternal infection?
A single dose of co-amoxiclav
What are some key indications to perform an instrumental delivery?
The decision to perform an instrumental delivery is based on the clinical judgement of the midwife or obstetrician.
1) failure to progress
2) fetal distress
3) maternal exhaustion
4) control of the head in various fetal positions
How does an epidural affect chance of requiring an instrumental delivery?
There is an increased risk of requiring an instrumental delivery when an epidural is in place for analgesia.
What is the ventouse?
An instrument that attaches a cup to the fetal head via a vacuum. The suction cup goes on the baby’s head, and the doctor or midwife applies careful traction to the cord to help pull the baby out of the vagina.
The most common are:
1) An electrical pump attached to a silastic cup.
2) A hand-held, disposable device commonly known as the “Kiwi”.
When is ventouse comprised of an electrical pump attached to a silastic cup only suitable?
This is only suitable if the fetus is in an occipital-anterior position.
What foetal positions can the ventouse comprised of a hand-held, disposable device commonly known as the “Kiwi” be used for?
This is an omni-cup – it can be used for all fetal positions, and rotational deliveries.
To use the ventouse, where is the cup applied?
The cup is applied with its centre over the flexion point on the fetal skull (in the midline, 3cm anterior to the posterior fontanelle).
Where is the flexion point on the foetal head?
In the midline, 6 cm posterior to the anterior fontanelle or 3 cm anterior to the posterior fontanelle.
What is the main foetal complication of using a ventouse?
Cephalohaematoma: a collection of blood between the skull and the periosteum.
How are forceps used in delivery?
They come as two pieces of curved metal that attach together, go either side of the baby’s head and grip the head in a way that allows the doctor or midwife to apply careful traction and pull the head from the vagina.
What are 3 types of forceps?
1) Rhodes, Neville-Barnes or Simpsons – used for OA positions.
2) Wrigley’s – used at Caesarean section.
3) Kielland’s – used for rotational deliveries.
What is the OA position?
The best position for the baby to be in to pass through the pelvis: with head down and the body facing towards the mothers back.
This is known as occiput anterior (OA).
What is the main foetal complication of using forceps in delivert?
Facial nerve palsy, with facial paralysis on one side.
Foetal complications of forceps delivery?
1) Facial nerve palsy
2) Bruising on baby’s face
3) Baby can develop fat necrosis, leading to hardened lumps of fat on their cheeks (this resolves spontaneously over time).
What should the decision to perform an operative vaginal delivery be based on?
The entire clinical scenario in the 2nd stage of labour.
There are two questions that should be asked:
1) Is there a valid clinical indication to intervene?
2) Is the patient a suitable case for an instrumental delivery?
What defines inadequate progress in nulliparous women?
As a general rule, expect delivery after two hours of active pushing.
If no urge to push is felt at the diagnosis of second stage (common with regional anaesthesia), an hour can be allowed for fetal descent before starting active pushing.
What defines inadequate progress in multiparous women?
Expect delivery with one hour of active pushing, with an hour for descent if needed prior to active pushing.
What are some foetal indications for performing an instrumental delivery?
1) Suspected fetal compromise in the second stage of labour, usually diagnosed by:
- CTG monitoring
- Abnormal fetal blood sample
2) Clinical concerns e.g significant antepartum haemorrhage
What are some absolute contraindications to instrumental delivery?
1) Unengaged fetal head in singleton pregnancies.
2) Incompletely dilated cervix in singleton pregnancies.
3) True cephalo-pelvic disproportion (where the fetal head is too large to pass through the maternal pelvis).
4) Breech and face presentations, and most brow presentations.
5) Preterm gestation (<34 weeks) for ventouse.
6) High likelihood of any fetal coagulation disorder for ventouse.
In general, what are the pre-requisites for performing an instrumental delivery?
1) fully dilated
2) ruptured membranes
3) cephalic presentation
4) defined foetal position
5) foetal head at least at the level of the ischial spines, and no more than 1/5 palpable per abdomen
6) empty bladder
7) adequate pain relief
8) adequate maternal pelvis
What presentation must the foetus be in to perform an instrumental delivery?
Cephalic presentation
How are operative vaginal deliveries classified?
By the degree of foetal ascent:
1) Outlet
2) Low
3) Midline
The lower the classification, the less the risk of complications.
What defines an ‘outlet’ classification of operative vaginal delivery?
Any of the following:
1) Fetal scalp visible with labia parted
2) Fetal skull reached pelvic floor
3) Fetal head on perineum
What defines a ‘low’ classification of operative vaginal delivery?
Lowest presenting part (not caput) is +2, or further below the ischial spines.
Subdivided to:
> 45 degrees – rotation needed
<45 degrees – no rotation needed
What defines a ‘midline’ classification of operative vaginal delivery?
1/5 palpable abdominally
Lowest part is above +2, but is lower than the ischial spines
Subdivided to:
> 45 degrees – rotation needed
<45 degrees – no rotation needed
Give some foetal complications of an instrumental delivery
1) Neonatal jaundice
2) Scalp lacerations
3) Cephalhaematoma
4) Subgaleal haematoma
5) Facial bruising
6) Facial nerve damage
7) Skull fractures
8) Retinal haemorrhage
Give some maternal complications of instrumental delivery
1) Vaginal tears
2) 3rd/4th degree tears
3) VTE
4) Incontinence
5) PPH
6) Shoulder dystocia
7) Infection
Rarely an instrumental delivery may result in nerve injury for the mother.
What are the 2 most commonly affected nerves?
1) femoral nerve
2) obturator nerve
How can the maternal femoral nerve be injured during instrumental delivery?
The femoral nerve may be compressed against the inguinal canal during a forceps delivery.
How can injury to the maternal femoral nerve during instrumental delivery present?
1) weakness of knee extension
2) loss of patella reflex
3) numbness of anterior thigh and medial lower leg
How can the maternal obturator nerve be injured during instrumental delivery?
May be compressed by forceps during instrumental delivery (or by the fetal head during normal delivery).
How can injury to the maternal obturator nerve during instrumental delivery present?
1) weakness of hip adduction and rotation
2) numbness of medial thigh
What are three other nerve injuries can occur during birth that are usually unrelated to instrumental delivery?
1) Lateral cutaneous nerve of the thigh
2) Lumbosacral plexus
3) Common peroneal nerve
Where does the lateral cutaneous nerve of the thigh run?
Under the inguinal ligament
How can the lateral cutaneous nerve of the thigh be injured during delivery?
Prolonged flexion at the hip while in the lithotomy position can result in injury.
How does damage to the lateral cutaneous nerve of the thigh during delivery present?
Numbness of the anterolateral thigh.
How can the lumbosacral plexus be injured during delivery?
The lumbosacral plexus may be compressed by the fetal head during the second stage of labour.
How does damage to the lumbosacral plexus during delivery present?
Injury to this network of nerves nerve can cause foot drop and numbness of the anterolateral thigh, lower leg and foot.
How can the common peroneal nerve be injured during delivery?
The common peroneal nerve may be compressed on the head of the fibula whilst in the lithotomy position.
How does damage to the common peroneal nerve during delivery present?
Injury to this nerve causes foot drop and numbness in the lateral lower leg.
