Abnormal lie and breech presentation Flashcards
What is abnormal lie?
• The lie of the foetus describes the relationship of the foetus to the long axis of the uterus
if lying longitudinally, the lie is longitudinal and presentation is cephalic or breech
if neither is palpable at the pelvic inlet, then the foetus must be lying across the uterus with the head in one iliac fossa (oblique lie) or in the flank (transverse lie)
• Abnormal lie occurs at 1 in 200 births, more common earlier in pregnancy and before term it is normal
What is the aetiology of abnormal lie?
• Preterm labour is more commonly complicated by an abnormal lie than labour at full term
polyhydramnios or high parity- allow the foetus to turn
foetal or uterine abnormalities and twin pregnancies- prevent turning
• Conditions that prevent engagement eg. placenta praevia, pelvic tumours and uterine deformities
What are the complications of an abnormal lie?
- If the head or breech cannot enter the pelvis, the labour cannot deliver the foetus
- An arm or the umbilical cord may prolapse when the membranes rupture- if neglected the obstruction eventually causes uterine rupture
- Both foetus and mother are at risk
What is the management for abnormal lie?
- No action is required for transverse or unstable lie <37 weeks unless the women is in labour
- > 37 weeks, the women is often admitted to hospital in case the membranes rupture and USS is preformed to exclude particular identifiable causes, notably polyhydramnios and placenta praevia
- External cephalic version (ECV) is unjustified because the foetus normally turns back
- If spontaneous version occurs and persists for >48hrs, then the mother is discharged
- In the absence of pelvic obstruction, an abnormal lie will usually stabilise before 41 weeks
- At 41 weeks or if the women is in labour- the persistently abnormal lie is delivered by C-section
What is breech presentation?
part of the foetus that occupies the lower segment of the uterus or the pelvis
occurs in 3-4% of term pregnancies, but more common if the labour is preterm (25%)
• Types of breech
o Extended breech (70%) has both legs extended at the knee
o Flexed breech (15%) has both legs flexed at the knee
o Footling breech (15%) has one or both feet present below the buttocks
upper abdominal discomfort is common and USS confirms diagnosis- ensures the prerequisites for
ECV are met
• Perinatal and long-term morbidity and mortality are increased
What is external cephalic version?
• From 37 weeks an attempt is made to turn the baby to a cephalic presentation- this reduces breech presentation at term and therefore C-sections success rate is 50%, but approximately 3% of those will turn back
where ECV fails, 3% will turn spontaneously before delivery
• ECV is done by administering a tocolytic (uterine relaxant) to the mother
performed under USS guidance and in hospital to allow immediate delivery if complications occur
CTG is performed straight after and anti- D given if required
What are lower rates of success fo ECV seen in?
o Nulliparous women o Caucasians o Engaged breech o Head is not easily palpable o High uterine tone o Obese women o Reduced liquor volume
When is ECV not performed?
o The foetus is compromised
o Vaginal delivery is contraindicated (praevia),
o There are twins
o The membrane has ruptured
o There has been a recent antepartum haemorrhage
How is a breech infant delivered?
most breech presentations will undergo elective C-section
Vaginally if late presentation or a 2nd twin
• Vaginal birth is probably more risky with a foetus >3.8kg
• Pushing is discouraged until the buttocks are visible and CTG is advised, in 30% of cases there is a slow 1st stage or 2nd stage, so C-section is advised
As buttocks distend the perineum, perform the episiotomy. Finger behind the knee delivers the legs. Hook each arm down. Forceps delivering the head once the arms are delivered
