Malposition & Malpresentation (incl. breech, unstable lie, ECV)

Question 1

What is a breech presentation?

Answer 1

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

Question 2

What are the types of breech presentation?

Answer 2

• 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

Question 3

How common is breech presentation before and at term?

Answer 3

Whilst around 25% of pregnancies at 28 weeks are breech it only occurs in 3% of babies near term.

Question 4

What is a footling breech? What is the problem with it?

Answer 4

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

Question 5

What dangerous complication is more common in breech presentation?

Answer 5

Cord prolapse is more common in breech presentations

Question 6

What are the risk factors for breech presentation?

Answer 6

• prematurity (due to increased incidence earlier in gestation)
• fetal abnormality (e.g. CNS malformation, chromosomal disorders)
• uterine malformations, fibroids
• placenta praevia
• polyhydramnios or oligohydramnios

Question 7

What is the management of breech presentation?

Answer 7

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)

Question 8

What is ECV?

Answer 8

External cephalic version (ECV) is the manipulation of the fetus, through the maternal abdomen, to a cephalic presentation.

Question 9

What medication can be given to improve the success rate of ECV?

Answer 9

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.

Question 10

When can you offer ECV?

Answer 10

36 weeks if nulliparus

37 weeks if multiparous

Question 11

When should you not use betamimetics?

Answer 11

If significant cardiac disease or HTN in mother

Not effective in those on BB

Question 12

What is the success rate of ECV?

Answer 12

~60%

Lower in nulliparous women than multiparous women

Question 13

What are the contraindications for ECV?

Answer 13

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

Question 14

What are the risks of ECV?

Answer 14

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

Question 15

Define foetal lie.

Answer 15

refers to the long axis of the foetus relative to the longitudinal axis of the uterus

Question 16

What are the types of foetal lie? Which is most and least common?

Answer 16

• 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.

Question 17

What is transverse lie and what are the two variants of it?

Answer 17

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

Question 18

How common is transverse lie?

Answer 18

Early in gestation, transverse lie is very common. Most have moved to longitudinal lie by 32 weeks.

At term, one in 300 foetuses are in transverse lie.

Question 19

What are the risk factors for transverse lie?

Answer 19

• Prematurity
• Most commonly occurs in women who have had previous pregnancies
• Pregnant with twins or triplets
• Foetal abnormalities
• Fibroids and other pelvic tumours
• Polyhydramnios

Question 20

How do you diagnose transverse lie?

Answer 20

Abdominal examination + confirmed with USS (assess FHR to check for distress)

Question 21

What are the complications of transverse lie?

Answer 21

PROM- Pre-term rupture membranes

Cord-prolapse (20%)

Question 22

What may happen when a transverse lie is allowed to progress to vaginal delivery?

Answer 22

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.

Question 23

What is the management of transverse lie?

Answer 23

Same as breech management i.e.

<36 weeks - do nothing

>36 weeks - ECV if wanting SVD (unless ruptured membranes in the last 7 days, multiple pregnancy except second twin and uterine abnormality) or C/S . Success rate ~50%.

Question 24

What factors must be taken into account when considering C/S?

Answer 24

• Perceived risk to mother and foetus
• Patient preference
• Previous pregnancies and co-morbidities
• Patient’s ability to access obstetric care rapidly

Question 25

Define unstable lie.

Answer 25

Fetus changes position frequently after 36/37 weeks gestation

Not sinister in multiparous women

May be a sign of placenta praevia in others which prevents enlargement of the fetal head

Other causes:

• polyhydramnios
• prematurity
• subseptate uterus
• pelvis tumours