MALPRESENTATION IN LABOUR Flashcards
What do we mean by malpresentation towards the end of pregnancy?
Any presentation other than a vertex presentation.
What is the vertex in terms of presentation of the fetus?
The vertex is the area between parietal eminences and the anterior and posterior fontanelles. The fetus will have its neck flexed with its chin tucked into its chest.
What are the different types of malpresentation?
Breech
Shoulder
Face
Brow
Transverse
What are the maternal causes and risk factors of malpresentation?
Contraction of the pelvis
Pelvic tumour eg fibroid
Mullerian abnormality
Multiparity
What are the fetoplacental causes and risk factors of malpresentation?
Prematurity
Placenta praevia
Polyhydramnios
Multiple pregnancy
Fetal abnormality
Fetal anomaly: Hydrocephalus Extension of fetal head by neck tumours Anencephaly Decreased fetal tone
What is the most common type of malpresentation?
Breech
What is the most important risk factor for breech presentation?
Prematurity
What is the incidence of breech presentation in term babies?
3%
What is the incidence of breech presentation in babies who are born at 32 weeks?
15%
What is the incidence of breech presentation in babies who are born at 28 weeks?
25%
What are the three main types of breech presentation? Describe each one.
Extended or frank breech presentation - hips are flexed and the knees are extended with feet situated adjacent to the head.
Flexed or complete breech presentation - flexion at both the hips and knees with feet at same level as breech
Footline breech presentation - flexion at both hips and knees but with feet present to the maternal pelvis not the breech
What is the most common type of breech presentation?
Extended or frank breech - 50%
If there is doubt about malpresentation from palpation what should be done for the patient?
Ultrasound to confirm
What are the complications associated with breech presentations at labour?
Increased perinatal mortality and morbidity - usually associated with delivering the head once the rest has delivered.
Intracranial injury - no time for head moulding as head will compress cord
Hypoxic-ischemic encephalopathy
Cord prolapse
Spinal cord injury
Adrenal haemorrhage
Fractures of clavicle or humerus
What is a nuchal arms delivery?
This is when the arms get trapped up along with the head and allows for even less space through the pelvis.
What are the three management options for a breech presentation?
External cephalic version (ECV)
Elective caesarian section
Planned vaginal breech delivery
What is external cephalic version?
This is an attempt to turn the baby inside the womb to cephalic presentation, by massaging the fetus first into transverse lie and then rolling over into the cephalic presentation.
When should external cephalic version be attempted?
At 37 weeks.
What are the contraindications to external cephalic version.
Pelvic masses
Antepartum haemorrhage
Placenta praevia
Previous caesarian section or hysterotomy
Multiple pregnancy
Ruptured membrane
What medications should be given if external cephalic version is to be attempted?
Tocolytics can be used to reduce uterine activity
Anti-D should be given if mother is rhesus negative
What measures should be taken if the mother decides to proceed with a vaginal breech delivery?
Check estimated fetal weight - above 4kg should indicate caesarian section
Continuous fetal heart measurement
Must exclude cord prolapse when membranes rupture or if fetal heart rate becomes abnormal
Epidural anaesthesia is recommended because of increased manipulation required.
Routine episiotomy
What is the success rate of vaginal breech delivery?
About 50% as there is such a low threshold for doing caesarian section that most will never get far enough.
What is Lovset’s manoeuvre?
This is a manoeuvre performed to keep the spine anterior and aims to reduce the incidence of nuchal arms.
What is the Mauriceau-Smellie-Veit manoeuvre?
Improves flexion of head to allow easier delivery.
What is the definition of unstable lie?
This is when, after 37 weeks, the fetal lie is found to be in a different orientation at each palpation.
What is the incidence of transverse lie in labour?
1 in 500
What should you check before doing a vaginal examination of a patient with a fetus in transverse lie?
Placenta praevia should be excluded
What risk factors particularly increase the likelihood of the fetus being in transverse lie at labour?
Multiparity - reduced tone of uterus
Premature labour
The second twin is more likely to be in transverse lie
What is the most serious complication of transverse lie?
Cord prolapse
How do you manage someone who presents with transverse or unstable lie after 37 weeks?
Exclude cause of malpresentation such as placenta praevia
ECV can be attempted if no such cause is found and as long as membranes have not ruptured
If reversion to malpresentation occurs or an unstable lie is diagnosed then admission to hospital from 37 weeks is indicated when immediate delivery is possible if membranes rupture.
At term, unstable lie can spontaneously vert to cephalic presentation and this can be managed normally.
ECV followed by immediate induction of labour and artificial rupture of membrane may work
If not caesarian section is indicated
What is face presentation?
This is when the fetus extends their neck and head rather than flexing.
What is the incidence of face presentation?
1 in 300
What are the risk factors for face presentation?
Congenital tumour of the neck
Anencephaly
What is the name and diameter of the widest part of the skull during face presentation?
Submento-bregmatic - 9.5 cm
When is diagnosis of face presentation usually made?
Vaginal examination in labour, when supraorbital ridges, bridge of the nose and mouth are palpable
Why is face presentation sometimes initially misdiagnosed as breech presentation?
The face become oedematous
With reference to the chin, what position must the fetus be lying in for vaginal delivery to be successful if face presentation is diagnosed?
Mentoanterior position
Mentoposterior position will not work as the head will not be able to be flexed.
How do we manage face presentation at labour?
Check that it is mentoanterior - initial mentoposterior presentation will spontaneously rotate to mentoanterior presentation in 50% of cases.
If mentoanterior - essentially the same as vertex presentation. Forceps can be used to correct delay.
If mentoposterior and not rotating - caesarian section
If fetal heart abnormalities, proceed to caesarian section as FBS should not be taken from face.
What is brow presentation in labour?
When the forehead and top of the head engage in the pelvis without head flexion. There is slight extension of the neck but not to the same degree as face presentation.
What is the incidence of brow presentation?
1 in 500
What are the risks and complications of presentation?
Early rupture of the membranes
Cord prolapse
What is the name and diameter of the widest part of the skull during brow presentation?
Submento-vertical - 13.5 cm
How do we manage patients with brow presentation?
Labour should be monitored but allowed to continue as extension to face presentation or flexion to vertex presentation are the most common outcomes.
Any failure to progress or fetal distress should lead to c-section.
