Abnormal Lie and Breech Presentation Flashcards
What does the ‘lie’ of the foetus describe?
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)
how many births does abnormal lie occur in?
1 in 200
more common earlier in pregnancy, and before term it is normal
Why does abnormal lie occur?
circumstances that allow the foetus to turn = most common cause e.g. polyhydramnios or high parity
conditions that prevent turning may also cause persistent transverse lie e.g. foetal or uterine abnormalities and twin pregnancies
Conditions that prevent engagement - e.g. placenta praevia, pelvic tumours and uterine deformities
What are the presentations of abnormal lie?
If the head or breech cannot enter 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 of abnormal lie?
No action <37 weeks unless the woman is in labour
> 37 weeks, woman is admitted to hospital in case the membranes rupture and USS is performed to exclude particular identifiable causes (polyhydramnios/placenta praevia)
ECV unjustified
Discharged if spontaneous version occurs
When does lie normal stabilise
Before 41 weeks in the absence of pelvic obstruction
How is a persistently abnormal lie managed at 41 weeks?
C-section
What is breech presentation?
Breech presentation refers to when the presenting part of the fetus (the lowest part) is the legs and bottom. This is opposed to cephalic presentation, where the head is the presenting part. Breech presentation occurs in less than 5% of pregnancies by 37 weeks gestation
What are the three different types of breech?
Complete breech, where the legs are fully flexed at the hips and knees
Incomplete breech, with one leg flexed at the hip and extended at the knee
Extended breech, also known as frank breech, with both legs flexed at the hip and extended at the knee
Footling breech, with a foot is presenting through the cervix with the leg extended
What other condition is commonly associated with breech presentation?
prematurity commonly associated with breech presentation
conditions that prevent movement or that prevent engagement of the head are more common
How is breech presentation diagnosed?
Commonly missed (30%)
diagnosis is only important from 37 weeks or if the woman is in labour
upper abdominal discomfort is common and USS confirms
What are the effects of breech presentation
perinatal and long-term morbidity and mortality are increased - foetal abnormalities are more common
Labour also has additional hazards of hypoxia and birth trauma
What is External cephalic version?
External cephalic version (ECV) is a technique used to attempt to turn a fetus from the breech position to a cephalic position using pressure on the pregnant abdomen. It is about 50% successful.
External cephalic version is used in babies that are breech:
After 36 weeks for nulliparous women (women that have not previously given birth)
After 37 weeks in women that have given birth previously
How is ECV done?
Women are given tocolysis to relax the uterus before the procedure with subcutaneous terbutaline.
Rhesus-D negative women require anti-D prophylaxis when ECV is performed. A Kleihauer test is used to quantify how much fetal blood is mixed with the maternal blood, to determine the dose of anti-D that is required.
In what situations is ECV less successful in?
Nulliparous women Caucasians Engaged breech head not easily palpable High uterine tone obese women reduced liquor volume
