Multiple Pregnancy

Question 1

How to estimate gestational age from USS

Answer 1

Largest baby to avoid the risk of estimating it from a baby with early growth pathology

Question 2

How to determine chorionicity and amnio I city

Answer 2

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

Question 3

When to additionally test for anaemia

Answer 3

20-24 weeks

Question 4

Triplet pregnancy 2nd trimester screening

Answer 4

Do NOT use

Question 5

When to refer to fetal med

Answer 5

EFW >25% discordance AND EFW of any of the babies is below the 10th centile

20% discordance in MCDA twins

Question 6

Monitoring in mono pregnancy for defo-fetal transfusion syndrome

Answer 6

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

Question 7

Diagnosis of feto-fetal transfusion syndrome

Answer 7

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

Question 8

Calculate EFW discordance

Answer 8

EFW larger fetus - EFW smaller fetus divided by EFW larger fetus

Question 9

TAPS monitoring

Answer 9

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

Question 10

No use in twin preg

Answer 10

Arabin peasant
Bed rest
Cervical cerclage
Oral tocolytics

Question 11

Number preterm births in twin pregnancies

Answer 11

60%

<32 weeks 9%

Question 12

Triplet births before 35 weeks

Answer 12

75%

Question 13

DCDA twins when to deliver

Answer 13

From 37 weeks
No increased risk of serious neonatal adverse outcomes
Continuing beyond 37 weeks increases the risk of fetal death 6-9:1000

Question 14

MCDA twins when to deliver

Answer 14

36 weeks

Question 15

MCMA twins when to deliver

Answer 15

32-33+6

Question 16

Tri tri or tri di

Answer 16

Deliver before 36 weeks

Question 17

When ok to try for vaginal birth for MCDA and DCDA

Answer 17

Uncomplicated
>32 weeks
No obstetric contraindications to labour
Lead twin cephalic
No significant size discordance between twins

Question 18

When to offer caeser for dcda or MCDA

Answer 18

Lead twin not cephalic at time of planned birth

Lead twin not cephalic and in prem labor between 26 and 32 weeks

Question 19

Time before need to bail out

Answer 19

Anything worrying, need to be able to deliver within 20 minutes (both babies out!)

Question 20

First USS

Answer 20

Between 11 and 13+6
Assess viability
Gestational age
Chorionicity
Exclude major congenital malformations

Question 21

MCDA twins compared to DCDA

Answer 21

Higher rate of fetal loss

Higher risk of associated neurodevelopmental morbidity

Question 22

MCDA USSs

Answer 22

Always assess LV and UAPI
Visualize fetal bladders
Fetal biometry from 16 weeks (2 weekly intervals)

Question 23

Maternal signs of TTTS

Answer 23

Sudden increase in abominable size

Breathlessness

Question 24

Quintero staging of TTTS

Answer 24

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

Question 25

TTTS studies at time of diagnosis

Answer 25

Quintero stage MCA PSV DV studies UA Doppler

Question 26

Treatment of TTTS before 26 weeks

Answer 26

Fetoscopic laser ablation

Question 27

Timing of del MCDA treated TTTS

Answer 27

Between 34-36+6

Question 28

Timing of delivery in selective growth restriction

Answer 28

Type 1 34-36 weeks | Type II and III - 32 unless abnormal or worsening dopplers

Question 29

Risk to other twin after death of twin in MCDA

Answer 29

Death 15% Neurological abnormality 26% Mechanism: hypotension and ischaemai

Question 30

Complications with inter-twin vascular anastomoses

Answer 30

``` TTTS SGR TAPS TRAP IUD ```

Question 31

Rate of TTTS

Answer 31

15%

Question 32

TAPS

Answer 32

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

Question 33

SGR grading

Answer 33

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)

Question 34

TRAP

Answer 34

1% MCDA Acardiac twin being perfumed by the anatomically normal pump twin through a large artery-artery anastomosis

Question 35

Epidemiology Birth rate Mortality Morbidity

Answer 35

15.8:1000 37:1000 8x greeter risk CP

Question 36

Embryology day division

Answer 36

Before day 3 - Dcda Day4-8 - MCDA Day 8-13 MCMA After that - conjoined twins

Question 37

Types of placental communication in MCDA

Answer 37

A-A: superficial V-V: superficial A-V: deep anastomoses; unidirectional flow

Question 38

Pathophysiology of TTTS of donor twin

Answer 38

``` Hypovolaemia in donor twin leads to: Activation renin-angiostensin system Increased ADH Results in: Vasoconstriction Oliguria Oligohydramnios Growth restriction ```

Question 39

Pathophysiology TTTS in recipient twin

Answer 39

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)

Question 40

Laser ablation survival, complications and loss

Answer 40

70% survival Complications:SROM, infection, miscarriage/preterm delivery Half result in the loss of one or both twins

Question 41

TRAP pump twin mortality cause

Answer 41

50% die CHF and hydrops OR Prematurity induced by polyhydramnios

Question 42

MCMA twins incidence and loss rate

Answer 42

2-5% of MC pregnancies 10-15% perinatal loss Largely due to cord entanglement

Question 43

Overall risk of congenital malformation in twins

Answer 43

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)

Question 44

Risk of neurological abnormality to second twin after one twin demises in MCDA

Answer 44

18%

Question 45

Management if one fetus demises

Answer 45

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

Question 46

TRAP

Answer 46

Twin reversed arterial perfusion sequence

Question 47

Incidence of multiple pregnancy

Answer 47

32 per 1000 livebirths Older mums Fertility treatment

Question 48

Maternal complications

Answer 48

``` Hyperemesis Anaemia GDM Preterm birth HTN VTE APH Polyhydramnios Operative delivery PPH Postnatal depression Maternal mortality 2.5x risk ```

Question 49

Fetal complications

Answer 49

``` Mortality Congenital abnormalities (structural, chromo) FGR Feeding difficulties Long term disability (CP 4-*x risk) ```

Question 50

TAPs fetal complications

Answer 50

Double IUD Neonatal anaemia/polycythaemia Neurodevelopmental impairment (20%)

Question 51

Acute fetal-fetal transfusion syndrome

Answer 51

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