Multiple Pregnancy

Question 1

Define monozygotic twins

Answer 1

Identical (single zygote)

Question 2

Define dizygotic twins

Answer 2

Non-identical (from two zygotes)

Question 3

How can twins be classified by the amnion?

Answer 3

Monoamniotic -> single amniotic sac
Diamniotic -> two seperate amniotic sacs

Question 4

How can twins be classified by the placenta?

Answer 4

Monochorionic - share a single placenta
Dichorionic - two seperate placentas

Question 5

What type of twins have the best outcomes?

Answer 5

Diamniotic Dichorionic -> have own blood supply and nutrients

Question 6

How can you identify the number of placentas/amnions in a twin pregnancy?

Answer 6

Ultrasound
Lambda sign or twin peak -> indicates two amnions and two placentas (think seperate placenta so can push between)
T sign -> one placenta and two amnions

Question 7

What are the risks of a multiple pregnancy to the mother?

Answer 7

Anaemia
Polyhydramnios
Hypertension
Malpresentation
Spontaneous preterm birth
Instrumental delivery or c-section
PPH

Question 8

What are the risks of a multiple pregnancy to the foetus?

Answer 8

Miscarriage
Stillbirth
Fetal growth restriction
Prematurity
Twin-twin transfusion syndrome
Twin anaemia polycythemia sequence
Congenital abnormalities

Question 9

Dizygotic twins are always

Answer 9

Dichorionic diamniotic

Question 10

How often should twin pregnancy be followed up on ultrasound?

Answer 10

Monochorionic - every 2weeks from 16w
Dichorionic - every 4 weeks from 20w

Question 11

What is twin to twin transfusion syndrome?

Answer 11

10% of monochrionic twin
Artery to artery connection in the placenta -> allows bidirectional blood flow between twins -> protective
No AA connection
If more artery to vein connection from AtoB than BtoA -> A is sending more blood to B, than gets back.
Twin B becomes anaemic -> loss rbc
Twin A has plentiful (recipient) -> overloaded
Twin B suffers hypoxia (donor) -> lower amniotic fluid volume.

Question 12

What is the diagnostic criteria for twin to twin transfusion?

Answer 12

One twim = oligohydramniosis = 2cm or less
One twim = polyhydramnios = 8cm or more

Question 13

What are the different stages of twin to twin transfusion syndrome?

Answer 13

1 - 2cm v 8cm amniotic fluid
2 - no bladder in donor
3 - strain on recipient heart
4 - hydrops due to HF in recipient
5 - one foetus has died

Question 14

What is the treatment of twin to twin transfusion syndrome?

Answer 14

Laser ablation
Only 65% of two surviving foetus
80% of one surviving.

Question 15

What is twin anaemia polycythemia syndrome?

Answer 15

Chronic similar to TTTS
One twins becomes anaemic whilst the other develops polycythemia

Question 16

What additional investigations do women pregnant with twins needed?

Answer 16

Anaemia screen - FBC
booking clinic
20w
28w

Question 17

When is planned birth offered for multiple pregnancies?

Answer 17

MC MA -> from 32 till 33+6
MC DA -> from 36 to 36+6
DC DA -> from 37 to 37+7
Before 35+6 for triplets

Corticosteroids are often given to help with lung maturation

Question 18

What mode of delivery should be used for twins?

Answer 18

MonoA = must have c-section due to risk of entanglement

DiA - vaginal if first is cephalic, elective c is first is not cephalic