Multiple Pregnancy Flashcards
How to estimate gestational age from USS
Largest baby to avoid the risk of estimating it from a baby with early growth pathology
How to determine chorionicity and amnio I city
Number of placental masses
Presence of amniotic membranes and membrane thickness
Lambda or T-sign
If USS after 14 weeks - also use discordant fetal sex
When to additionally test for anaemia
20-24 weeks
Triplet pregnancy 2nd trimester screening
Do NOT use
When to refer to fetal med
EFW >25% discordance AND EFW of any of the babies is below the 10th centile
20% discordance in MCDA twins
Monitoring in mono pregnancy for defo-fetal transfusion syndrome
USS every 14 days from 16 weeks until birth
Increase frequency to weekly if difference in dVP depth of 4cm or more between babies
Do MCA PSV after 20 weeks
Check growth, DVPs, bladder volumes, and UAPI each time
Diagnosis of feto-fetal transfusion syndrome
Amniotic sac of 1 baby DVP <2cm AND Amniotic sac of another baby has a DVP depth of -over 8cm before 20 weeks of pregnancy OR -over 10cm from 20 weeks
Calculate EFW discordance
EFW larger fetus - EFW smaller fetus divided by EFW larger fetus
TAPS monitoring
Weekly USS from 16 weeks using MCA PSV for
Feto-fetal transfusion syndrome that has been treated with laser therapy OR
Selective FGR (EFW discordance 25% and one baby below the 10th
No use in twin preg
Arabin peasant
Bed rest
Cervical cerclage
Oral tocolytics
Number preterm births in twin pregnancies
60%
<32 weeks 9%
Triplet births before 35 weeks
75%
DCDA twins when to deliver
From 37 weeks
No increased risk of serious neonatal adverse outcomes
Continuing beyond 37 weeks increases the risk of fetal death 6-9:1000
MCDA twins when to deliver
36 weeks
MCMA twins when to deliver
32-33+6
Tri tri or tri di
Deliver before 36 weeks
When ok to try for vaginal birth for MCDA and DCDA
Uncomplicated >32 weeks No obstetric contraindications to labour Lead twin cephalic No significant size discordance between twins
When to offer caeser for dcda or MCDA
Lead twin not cephalic at time of planned birth
Lead twin not cephalic and in prem labor between 26 and 32 weeks
Time before need to bail out
Anything worrying, need to be able to deliver within 20 minutes (both babies out!)
First USS
Between 11 and 13+6 Assess viability Gestational age Chorionicity Exclude major congenital malformations
MCDA twins compared to DCDA
Higher rate of fetal loss
Higher risk of associated neurodevelopmental morbidity
MCDA USSs
Always assess LV and UAPI
Visualize fetal bladders
Fetal biometry from 16 weeks (2 weekly intervals)
Maternal signs of TTTS
Sudden increase in abominable size
Breathlessness
Quintero staging of TTTS
1 bladder of donor twin still visible 2 bladder of donor twin no longer visible, no critical abnormal Doppler 3 critical abnormal Doppler waveforms 4 hydrops 5 demise of one or both twins
TTTS studies at time of diagnosis
Quintero stage
MCA PSV
DV studies
UA Doppler
Treatment of TTTS before 26 weeks
Fetoscopic laser ablation
Timing of del MCDA treated TTTS
Between 34-36+6
Timing of delivery in selective growth restriction
Type 1 34-36 weeks
Type II and III - 32 unless abnormal or worsening dopplers
Risk to other twin after death of twin in MCDA
Death 15%
Neurological abnormality 26%
Mechanism: hypotension and ischaemai
Complications with inter-twin vascular anastomoses
TTTS SGR TAPS TRAP IUD
Rate of TTTS
15%
TAPS
Signs of fetal anaemia in the donor and polycythaemia in recipient without significant oligo/polyhydramnios being present
Donor has elevated MCA PSV, opposite for recipient
2% MCDA
13% MCDA with laser ablation
Donor >1.5 MoM
Recipient <0.80 MoM
SGR grading
I growth discordance but positive diastolic velocities in both fetal umbilical arteries
II growth discordance with absent or reveresed EDV in one or both
III growth discordance with cyclical UA diastolic waveforms (intermittent AREDV)
TRAP
1% MCDA
Acardiac twin being perfumed by the anatomically normal pump twin through a large artery-artery anastomosis
Epidemiology
Birth rate
Mortality
Morbidity
15.8:1000
37:1000
8x greeter risk CP
Embryology day division
Before day 3 - Dcda
Day4-8 - MCDA
Day 8-13 MCMA
After that - conjoined twins
Types of placental communication in MCDA
A-A: superficial
V-V: superficial
A-V: deep anastomoses; unidirectional flow
Pathophysiology of TTTS of donor twin
Hypovolaemia in donor twin leads to: Activation renin-angiostensin system Increased ADH Results in: Vasoconstriction Oliguria Oligohydramnios Growth restriction
Pathophysiology TTTS in recipient twin
Hypervolaemia results in
Increased secretion of atrial natriuretic factor
Results in:
Polyuria
Polyhydramnios
HTN - may cause cardiac hypertrophy, hydrops, death (HTN caused by volume overload and passive transfer of angiotensin from donor twin)
Laser ablation survival, complications and loss
70% survival
Complications:SROM, infection, miscarriage/preterm delivery
Half result in the loss of one or both twins
TRAP pump twin mortality cause
50% die
CHF and hydrops
OR
Prematurity induced by polyhydramnios
MCMA twins incidence and loss rate
2-5% of MC pregnancies
10-15% perinatal loss
Largely due to cord entanglement
Overall risk of congenital malformation in twins
600 per 10000
MC twins have 2-3x higher risk than DC
MZ defects: holoprosencephaly, NTDs and cloacal extrophy
CHD - 9% (7% for MCDA, 57% for MCMA)
Risk of neurological abnormality to second twin after one twin demises in MCDA
18%
Management if one fetus demises
Delivery earlier doesn’t prevent any further damage and have complication of prematurity
Can consider MRI to diagnose neurological damage secondary to hypovolaemia
MCA surveillance ongoing
IUT if evidence of severe anaemia
TRAP
Twin reversed arterial perfusion sequence
Incidence of multiple pregnancy
32 per 1000 livebirths
Older mums
Fertility treatment
Maternal complications
Hyperemesis Anaemia GDM Preterm birth HTN VTE APH Polyhydramnios Operative delivery PPH Postnatal depression Maternal mortality 2.5x risk
Fetal complications
Mortality Congenital abnormalities (structural, chromo) FGR Feeding difficulties Long term disability (CP 4-*x risk)
TAPs fetal complications
Double IUD
Neonatal anaemia/polycythaemia
Neurodevelopmental impairment (20%)
Acute fetal-fetal transfusion syndrome
Sudden drop in pressure and/or HR of one twin
Sudden and large unidirectional flow from the co-twin ‘acute donor’
Consequences depend on size, type and direction of anastomoses
Large AV or AA connections allow larger volume of flow
May lead to death and severe brain injury
Laser protective
