Breech Theory Flashcards
Breech presentation definition
Where the presenting part of the fetus is the buttock or feet
(Prompt 2017)
Incidence of breech presentation
Common before 37/40, with a suggested incidence of 15% at 29-32 weeks, reducing to 3-4%. By 34/40 the majority of breech babies will turn to a vertex
(Mayes 2012)
Types of breech presentation
- Flexed/complete - the fetus sits with the thighs and knees flexed with the feet close to the buttock (10-15%)
- Extended/frank - the fetal thighs are flexed, the legs are extended at the knees and lie alongside the trunk, with the feet near the fetal head (45-50%)
- Footling presentation - one or both feet present below the fetal buttock, with the hips and knees extended (more common in preterm)
- Knee presentation - one or both knees present below the fetal buttock, with one or both hips extended and the knees flexed (35-45%)
(Mayes 2012)
Maternal causes of breech presentation
Primigravidae - firm abdominal and uterine muscle may prevent flexion of the fetal legs, especially when they are already extended
Uterine abnormalities - bicornuate uterus may restrict fetal movement and a previous breech birth may be strongly associated with a uterine abnormality
Uterine fibroid - can interfere with fetal activity or when situated in the lower uterine segment can prevent the fetal head from entering the lower pole of the uterus
Contracted pelvis - fetal head unable to enter the pelvic brim
Maternal alcohol or drug use - may lead to fetal hypotonia in which the lack of movement, reduced or restricted fetal activity making it difficult for the fetus to turn
Grande multiparity - lax abdominal and uterine muscles allows movement and may lead to an unstable lie
(Mayes 2012)
Fetal and placental causes of breech presentation
Oligohydramnios - reduced liqour volume restricts the ability of the fetus to turn in the uterus. The condition may also be associated with fetal abnormalities and fetal compromise
Placenta location - placenta praevia may prevent the fetal head from fitting into the lower uterine segment and entering the pelvis
Fetal abnormalities - hydrocephalus can prevent the fetal head engaging in the pelvis
Multiple pregnancy - usually insufficient space to turn
Polyhydramnios - over distension of the uterus enables the fetus to be more mobile
Prematurity - increased incidence at earlier gestation as smaller fetus has greater space
Impaired fetal growth, short umbilical cord and fetal death - compromised fetus may result in decreased fetal activity
(Mayes 2012)
What is ECV?
RCOG (2017) advise that women with a term breech presentation should be offered external cephalic version (ECV) unless there is an absolute contraindication. It is the manipulation of the fetus, through the maternal abdomen, to a cephalic presentation
Contraindications for ECV
- Absolute reason for LSCS
- Placenta praevia
- Multiple pregnancy
- Rhesus isoimmunisation
- Vaginal bleeding with 7
days - SROM
- IUD
If ECV is unsuccessful …
RCOG (2017) advise that women who have breech presentation at term following an ECV should be counselled on the risks and benefits of planned vaginal breech delivery versus a planned caesarean section
Benefits of planned caesarean section
- Leads to a small reduction in perinatal mortality compared to vaginal delivery
- Avoidance of stillbirth after 39/40
- Avoidance of intrapartum risk
(RCOG 2017)
Risks of caesarean section
- Needs to be balances against the potential adverse outcomes (damage to the bowel or bladder and increased chance of stillbirth in future pregnancies RCOG 2019)
- Small increase in immediate complications for the mother compared to vaginal birth
(RCOG 2017)
Risks of perinatal mortality with caesarean section and vaginal birth
Caesarean after 39/40 = 0.5/1000
Planned vaginal breech birth = 2.0/1000
Planned cephalic birth = 1.0/1000
(RCOG 2017)
Benefits of planned vaginal breech birth
- A selection of appropriate pregnancies and skilled intrapartum care may allow planned vaginal breech birth to be nearly as safe as planned vaginal cephalic birth
- Small reduced risk of immediate complications for the mother compared to planned CS but the risk is highest with emergency CS which is needed in approximately 40% of planned vaginal breech birth
(RCOG 2012) - No shown increase in the risk of long term morbidity for babies
(RCOG 2017)
Risks of planned vaginal breech birth
- Increased risk of low APGAR scores and serious short
- Small increased risk of perinatal morality
(RCOG 2017)
Hannah term breech trail
Found breech vaginal deliveries to be unsafe which lead to routine caesareans. A follow up trail 10 years later showed there was no increased long term risk, even with short term consequences
Breech positions
- Left sacroanterior
- Left sacrolateral
- Left sacroposterior
- Right sacroanterior
- Right sacrolateral
- Right sacroposterior
(Mayes 2012)
What breech positions allow descent?
With the breech in either the left or right sacroanterior position and good contractions, there is descent
(Mayes 2012)