Management of monochorionic twin pregnancy GT51 and NICE 129 Multiple Pregnancy Flashcards
At what gestation should an USS be performed to determine chorionicity?
11+0 - 13+6
CRL 45-84mm
What is the USS surveillance for MC twins following detailed anatomy scan?
Every 2 weeks from 16+0 until delivery
Which parameters should be measured on USS for MC twins?
Deepest vertical pocket (LV)
Umbilical dopplers
Visualise fetal bladders
EFW
What does TAPS stand for?
In how many cases does it occur post-laser treatment
Twin anaemia-polycythaemia sequence - discordant Hb levels with NO significant oligo/polyhydramnios. ‘Slow’ transfusion
Screened for using MCA dopplers following e.g. laser treatment for TTTS or other complicated MC twins e.g. selective growth restriction
In 13% cases post laser ablation; 2% spontaneously
What % EFW discordance is associated with increased perinatal risk in MC twins?
In how many MC pregnancies does it occur (with/without TTTS)?
20%
Without TTTS - 15%
With TTTS - >50%
How is TTTS staged?
Quintero staging I - V
Laser > Stage 2 or more
What is the recommended treatment of TTTS presenting <26/40?
Fetoscopic laser ablation (Solomon technique) > amnioreduction or septostomy
What is the surveillance of MC twins following treatment for TTTS?
Weekly detailed USS (brain, heart, limbs) and serial umb Dopplers, MCA PSV, DV Dopplers.
2/52 after treatment back to 2/52 surveillance if all well
By when should MC twins previously complicated by TTTS be delivered?
34+0 - 36+6
What is the % of death and neurological abnormality in the surviving co-twin following death of an MC twin?
Death - 15%
Neuro - 26%
How should neuro morbidity be determined following the death of a MC co-twin?
Fetal MRI 4/52 after demise (if adds value to management)
When should otherwise uncomplicated MC twins be offered delivery?
From 36+0/40 after steroids unless earlier indication
Vaginal if diamniotic, unless other indications
By when should MCMA twins be delivered?
32+0 and 34+0 weeks by Caesarean Section
What % of twin pregnancies in the UK are MC?
And what proportion of these are MCMA?
30%
MCMA 1% of these
At which stage embryo transfer is monozygosity highest?
5 day blastocyst > 3/7 cleavage stage
What are the complications of inter-twin vascular anastomoses?
- TTTS
- Sel. growth restriction
- TAPS (twin anaemia-polycythaemia sequence) 2% uncomplicated MC; 13% post laser ablation
- TRAP sequence (twin reversed arterial perfusion) 1% MC pregnancies
- Single IUD
In what % of cases do MC twin placentas have bidirectional vascular anastomoses
80%
What % of MC pregnancies are complicated by TTTS?
15%
What is TRAP sequence?
twin reversed arterial perfusion
‘Acardiac’ twin being perfused by ‘normal’ pump twin
How is sGR staged in MC twin pregnancies?
I - Growth discordance, both + EDV
II - Growth discordance, AREDV in one or both fetuses
III - Growth discordance, cyclical umbilical artery diastolic waveforms (ie intermittent AREDV)
What % of MC placentas are bilobed?
3%
How is TTTS diagnosed ultrasonigraphically?
- Significant AF discordance (2/8cm; 10 if >20/40)
- Discordant bladder appearances
- Haemodynamic and cardiac compromise in both twins
What is the prevalence of conjoined twins and what is the survival rate?
1 in 90,000-100,000 pregnancies
Survival - 25%, majority with significant morbidity
What is the multiple pregnancy rate and what % of total live births does it constitute?
16/1000 in 2009
3% total live births
Makes up 24% of successful IVF treatments
What is the increase in perinatal mortality with a multiple pregnancy?
x2.5
What is the stillbirth rate for multiple pregnancy?
Twins 12.3/1000
Triplets 31.1/1000
20% secondary to TTTF
B/G 5/1000 singleton
What is the preterm birth rate for multiple pregnancy?
50%
10% will be <32/40
How much more common are major congenital abnormalities with multiple pregnancy?
4.9% more common
What % of unexplained stillbirth with multiple pregnancies are associated with BW<10th centile?
66%
39% singletons
When should MCDA twins be delivered?
From 36/40
When should DCDA twins be delivered?
37/40
When should triplets be delivered
35/40
