Malposition & Malpresentation (incl. breech, unstable lie, ECV) Flashcards
What is a breech presentation?
Caudal end of the fetus occupies the lower segment
A frank breech is the most common where the hips are flexed and knees fully extended
What are the types of breech presentation?
- Footling - both feet are extended at the hips and one or both are extended at the knee
- Flexed (complete) - hips and feet are flexed, looks like sitting with legs crossed
- Frank (incomplete) - hips and feet are extended
How common is breech presentation before and at term?
Whilst around 25% of pregnancies at 28 weeks are breech it only occurs in 3% of babies near term.
What is a footling breech? What is the problem with it?
A footling breech, where one or both feet come first with the bottom at a higher position,
It is rare but carries a higher perinatal morbidity
What dangerous complication is more common in breech presentation?
Cord prolapse is more common in breech presentations
What are the risk factors for breech presentation?
- prematurity (due to increased incidence earlier in gestation)
- fetal abnormality (e.g. CNS malformation, chromosomal disorders)
- uterine malformations, fibroids
- placenta praevia
- polyhydramnios or oligohydramnios
What is the management of breech presentation?
If < 36 weeks:
- Nothing - many fetuses will turn spontaneously
If still breech at 36 weeks:
- ECV recommended by NICE
- RCOG recommend ECV should be offered
- from 36 weeks in nulliparous women
- and from 37 weeks in multiparous women
If ECV unsuccessful, delivery options include planned C section (or rarely vaginal delivery)
What is ECV?
External cephalic version (ECV) is the manipulation of the fetus, through the maternal abdomen, to a cephalic presentation.
What medication can be given to improve the success rate of ECV?
Use of tocolysis with betamimetics improves the success rates of ECV.
Routine use of regional analgesia or neuraxial blockade is not recommended, but may be considered for a repeat attempt or for women unable to tolerate ECV without analgesia. Analegesia may prevent pain sensation which is important if there is rupture.
When can you offer ECV?
36 weeks if nulliparus
37 weeks if multiparous
When should you not use betamimetics?
If significant cardiac disease or HTN in mother
Not effective in those on BB
What is the success rate of ECV?
~60%
Lower in nulliparous women than multiparous women
What are the contraindications for ECV?
No general concensus. Can still be done if previously had C/S.
- multiple pregnancy
- major uterine anomaly
- where caesarean delivery is required
- antepartum haemorrhage within the last 7 days
- ruptured membranes
- abnormal CTG
What are the risks of ECV?
RARE
- Placental abruption
- Large fetomaternal haemorrhage
- Emergency C/S within 24 hours (0.5%)
- Rhesus sensitisation - so must undergo testing if D negative and be offerred anti-D
Define foetal lie.
refers to the long axis of the foetus relative to the longitudinal axis of the uterus
What are the types of foetal lie? Which is most and least common?
- longitudinal lie (99.7% of foetuses at term)
- transverse lie (<0.3% of foetuses at term)
- oblique (<0.1% of foetuses at term)
Causes and management options for transverse and oblique lie are the same, although oblique is easier to correct because the foetus is closer to longitudinal lie.
What is transverse lie and what are the two variants of it?
Transverse lie = foetal longitudinal axis lies perpendicular to the long axis of the uterus
- Scapulo-anterior - (most common) where the foetus faces towards the mother’s back
- Scapulo-posterior - oetus faces towards the mothers front
What may happen when a transverse lie is allowed to progress to vaginal delivery?
Compound presentation may occur. This is extremely rare in the UK.
Complications of compound presentation:
- Arrested labor.
- Dystocia.
- Cord prolapse.
- Injury to the presenting extremity.
