Twins

Question 1

% of monochorionic preg

Answer 1

30% of twins

Question 2

Complications for mum

Answer 2

• PTB
• FGR
• PET
• PPH
• PN complications- Adverse mood changes, feeding diff

Question 3

Complications for fetus

Answer 3

• TTTS
• sGR
• TAPS (T anaemia-polycythaemia seq)
• TRAP (reverse arterial perfusion)
• Single IUD

Question 4

Twins risk bases on type

Answer 4

MCMA - highest risk of loss <24w
MCDA
DCDA - least risk but still higher than singleton

Higher neuro disability in MC also

Question 5

TTTS- mainly in MCDA

Answer 5

• Affect 15% of MC preg
• Usually BEFORE 26w
• Unidirectional blood flow
• Affects fetal cardiac, placenta, renal function

Question 6

TTTS staging

Answer 6

I - sig discordance in LV
DVP <2cm in donor and >8cm in recipient
Normal doppler and bladder.

II - Bladder of donor not visible, severe oligo.
Doppler not critically abnormal.

III - Dopplers are critically abnormal

IV - Ascites, pericardial/pleural effusion, scalp oedema or hydrops in recipient

V- one or both babies have died

Question 7

TTTS mx

Answer 7

Stage I - might only need monitoring

• If <26w- Laser ablation - Soloman technique
  In tertiary centre (at least 15procedures/year)
• Weekly scan for 2 weeks then back to every 2 week scans
• > 26w- consider amnio- reduction

Question 8

TTTS recurrence

Answer 8

14% of preg treated w laser w or wo TAPS

Question 9

TAPS

Answer 9

• 13% of twin after laser ablation for TTTS
  or 2% of twins
• Slow tx of blood from donor to recipient
• Anaemia in donor (MCA PSV >1.5x normal)
  Recipient ( MCA PSV <1.0)
• No oligo/poly

Question 10

TAPS mx

Answer 10

• Difficult to mx due to very small anastomosis
• Mx with laser, IU tx
• Outcomes can vary

Question 11

Selective GR %

Answer 11

• 15% of MC twin wo TTTS
• 50% w TTTS
• Wt difference >20%

Diff to TTTS as one will be oligo and other normal LV

Question 12

sGR staging

Answer 12

I - growth discordance but + diastolic flow in both umbilical arteries.
90% survival

II - Growth discordance w absent or reversed EDV.
29% risk of demise

III - GD w cyclical UA diastolic waveforms, intermittent AREDV.
10-20% risk of demise

Question 13

sGR mx

Answer 13

• Selective reduction- inc risk of neuro disability in surviving T
• sGR delivery-
  T I- 34-36w
  T II/ III- 32 weeks

or cCTG STV <4.0

Question 14

Impact on surviving T after fetal death of co-twin

Answer 14

• 15% risk of death
• 26% risk of neuro disability

Question 15

Monitoring of surviving twin

Answer 15

• Fetal MRI 4 weeks after twin death
• Monitor MCA PSV for anaemia
• Delivery only if close to term

Question 16

Diagnosis of twins

Answer 16

• Dating scan (11-14w)- Determine chorionicity based on placental mass and membrance thickness
• Save photo electronically and in pt notes of membrance attachment
• If unsure, take photo to get 2nd opinion
• If still unsure, urgent FM review

Chorionicity should be known before 14w

Question 17

Aneuploidy screening

Answer 17

MC- overall preg risk, DC- fetus specific risk

• CST at 11-13+6 (higher false positive (10%) than singleton (2.5%))
• Quad test after

NIPT if high risk outcome

Question 18

Anomaly scan

Answer 18

Routine at 18-20 weeks
No need for specialist scan ie cardiac unless concerns

Question 19

USS f/u for twins

Answer 19

MC-
Every 2 weeks from 16 weeks.
Check DVP, umbilical artery doppler, EFW, bladder.

DC-
Every 4 weeks from 24 weeks

Question 20

Dopplers if suspected TTTS

Answer 20

• UAPI
• MCA PSV and pulsatility index
• DV doppler

Question 21

Growth discordance calculation

Answer 21

(Smaller T- larger T)/ Large T x 100

Question 22

Delivery

Answer 22

MCMA- 32-34w by CS
High risk of cord entanglement

MCDA uncomplicated- 36w onwards

MCDA w TTTS/TAPS prev- Deliver bet 34-36+6

DCDA- 37 weeks

Question 23

Selective reduction

Answer 23

• Offer to all preg >2
• Offer before any ivasive testing ie. Amnio
• Use laser ablation for monochorionic T
• Monitoring of DIC is not needed in SR