Multiple pregnancy

Question 1

Definition

Answer 1

Pregnancy with more than one fetus. The incidence of multiple pregnancies increased with the development of fertility treatment

Question 2

Types

Answer 2

• Monozygotic: identical twins (from a single zygote)
• Dizygotic: non-identical (from two different zygotes)
• Monoamniotic: single amniotic sac
• Diamniotic: two separate amniotic sacs
• Monochorionic: share a single placenta
• Dichorionic: two separate placentas

Question 3

Which type of multiple pregnancy has the highest chance of best outcome

Answer 3

Diamniotic,
Dichorionic

Question 4

Diagnosis

Answer 4

Booking USS:
- Gestational age
- Number of placentas (chorionicity) and amniotics sacs (amniocity)
- Risk of down’s syndrome (as part of the combined test)

Question 5

Dichorionic diamniotic twins on USS

Answer 5

Membrane between the twins, with a lambda sign or twin peak sign

Question 6

Monochorionic diamniotic twins on USS

Answer 6

Have a membrane between the twins with a T sign

Question 7

Monochorionic monoamniotic twins USS

Answer 7

No membrane separating the twins

Question 8

What is the lamba sign/twin peak sign

Answer 8

A triangular appearance where the membrane between the twins meets the chorion, as the chorion blends partially into the membrane = seen in dichorionic twins

Question 9

T sign

Answer 9

Where the membrane between the twins abruptly meets the chorion, giving a T appearance = monochorionic twin pregnancy.

Question 10

Complications to the mother

Answer 10

• Anaemia
• Polyhydramnios
• Hypertension
• Malpresentation
• Spontaneous preterm birth
• Instrumental delivery or caesarean
• Postpartum haemorrhage

Question 11

Complications for fetuses and neonates

Answer 11

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

Question 12

Twin twin transfusion syndrome

Answer 12

When fetuses share placenta.
- Called feto-fetal transfusion syndrome > 2 fetuses present.
- There is a connection between the blood supplies of the two fetuses, one fetus (the recipient) may receive the majority of the blood from the placenta, while the other fetus (the donor) is starved of blood. - The recipient can become fluid overloaded - Heart failure and polyhydramnios
- The doner - growth restriction, anaemia and oligohydramnios
- There will be a discrepancy between the size of the fetuses.

Question 13

Twin anaemia polycythaemia sequence

Answer 13

Similar to twin-twin transfusion syndrome = but less acute.
One twin becomes anaemic whilst the other develops polycythaemia (raised haemoglobin)

Question 14

Antenatal care

Answer 14

• A specialist multiple pregnancy obstetric team manages women with MP
• Women with multiple pregnancies require additional monitoring for anaemia, with a full blood count at:
  = Booking clinic
  = 20 weeks gestation
  = 28 weeks gestation
• Additional USS required to monitor for:
  1. Fetal growth restriction
  2. Unequal growth
  3. Twin-twin transfusion syndrome
  = 2 weekly scans from 16 weeks for monochorionic twins
  = 4 weekly scans from 20 weeks for dichorionic twins

Question 15

Planned birth offered when

Answer 15

= 32 and 33 + 6 weeks for uncomplicated monochorionic monoamniotic twins
= 36 and 36 + 6 weeks for uncomplicated monochorionic diamniotic twins
= 37 and 37 + 6 weeks for uncomplicated dichorionic diamniotic twins
= Before 35 + 6 weeks for triplets

Question 16

Risk of late delivery for twins

Answer 16

Increased risk of fetal death.
- The timing of birth when there are complications is assessed on an individual basis.
- Corticosteroids are given before delivery to help mature the lungs.

Question 17

Delivery

Answer 17

• Monoamniotic twins require elective caesarean section at between 32 and 33 + 6 weeks.
• Diamniotic twins (aim to deliver between 37 and 37 + 6 weeks):
  = Vaginal delivery is possible when the first baby has a cephalic presentation (head first)
  = C-section may be required for the second baby after successful birth of the first baby
  = Elective caesarean is advised when the presenting twin is not cephalic presentation