Twin & Triplet Pregnancy

Question 1

How are chorionicity & amnionicity determined by ultrasound?

Answer 1

1. Number of placental masses
2. Presence of amniotic membrane & membrane thickness
3. Lambda (DCDA) or T (MCDA) sign

Question 2

What should be the ANC & scan schedule for DCDA twins?

Answer 2

8 appts
Both at dating, 20, 24, 28, 32, 36
ANC at 16, 34
At least 2 of these with specialist obstetrician

Question 3

What should be the schedule for ANC & scans for MCDA twins?

Answer 3

11 appts
Both at booking then fortnightly from 16/40
At least 2 of these with specialist obstetrician

Question 4

How often should fetal growth discordance be monitored for in multiple pregnancy?

Answer 4

1. Every 4 weeks in DC twins
2. Every 2 weeks in TC triplets
3. Every 2 weeks in MC
4. Weekly if concerns: discordance >20%, any < 10th centile

Question 5

What triggers diagnosis of feto-fetal transfusion syndrome?

Answer 5

1. Amniotic sac of 1 baby has DVP < 2 cm AND
2. Amniotic sac of other baby has DVP > 8cm before 20/40 or > 10cm from 20/40

Question 6

How is TAPS monitored for?

Answer 6

1. MCA-PSV
2. Weekly from 16/40 if feto-fetal transfusion syndrome or selective FGR
3. Cardiovascular compromise eg hydrops, cardiomegaly
4. Unexplained isolated polyhydramnios
5. Abnormal umbilical artery

Question 7

How is TAPS monitored for?

Answer 7

1. MCA-PSV
2. Weekly from 16/40 if feto-fetal transfusion syndrome or selective FGR
3. Cardiovascular compromise eg hydrops, cardiomegaly
4. Unexplained isolated polyhydramnios
5. Abnormal umbilical artery

Question 8

What preterm birth prevention strategies are used in multiple pregnancy?

Answer 8

1. Single cervical length scan 16-20/40
2. If this or incidental finding of Cx length < 25mm, offer PV progesterone:
   200mg ON to 34/40

Question 9

What proportion of twins are born spontaneously before 37/40?

Answer 9

60%

Question 10

What proportion of triplets are born before 35/40?

Answer 10

75%

Question 11

When should birth be planned for uncomplicated DCDA twins?

Answer 11

37-37+6/40

Question 12

When should birth be planned for uncomplicated MCDA twins?

Answer 12

36-36+6/40

Question 13

When should birth be planned for uncomplicated MCMA twins?

Answer 13

32-33+6/40

Question 14

When should birth be planned for uncomplicated triplets?

Answer 14

1. Trichorionic: before 35+6
2. Shared chorion: individualised

Question 15

What factors support a vaginal twin birth?

Answer 15

1. DCDA or MCDA
2. Uncomplicated pregnancy
3. Beyond 32/40
4. 1st baby is cephalic
5. No significant growth discordance

Question 16

What factors support a vaginal twin birth?

Answer 16

1. DCDA or MCDA
2. Uncomplicated pregnancy
3. Beyond 32/40
4. 1st baby is cephalic
5. No significant growth discordance

Question 17

What factors support a vaginal twin birth?

Answer 17

1. DCDA or MCDA
2. Uncomplicated pregnancy
3. Beyond 32/40
4. 1st baby is cephalic
5. No significant growth discordance

Question 18

What is the best intrapartum analgesia for multiple pregnancy?

Answer 18

Epidural, to improve success & also support emergency birth

Question 19

What is TAPS?

Answer 19

Twin anaemia polycythaemia sequence
Rare form of TTTS, without difference in amniotic fluid levels
Donor becomes anaemic, recipient becomes polycythaemic