Multiple Pregnancies

Question 1

What is a multiple pregnancy?

Answer 1

• when you are expecting two or more babies at the same time
• twins, triplets etc…

Question 2

What is perinatal?

Answer 2

• perinatal is time from pregnancy and up to 1 year following birth

Question 3

What is perinatal mortality?

Answer 3

• death of a foetus or baby

- during time from birth through to 1 year old

Question 4

Perinatal mortality refers to the death of a foetus or baby. Is perinatal mortality higher in individual or multiple pregnancy (twins etc..)?

Answer 4

• multiple pregnancy

Question 5

What are dizygotic twins?

Answer 5

• di = two
• zygotic = formation of a zygote from 2 gametes
• pregnancy but with 2 separate embryos , so NOT identical

Question 6

What are monozygotic twins?

Answer 6

• mono = one
• zygotic = formation of a zygote from 2 gametes
• one zygote splits into 2 separate groups of cell = can be IDENTICAL TWINS but not always

Question 7

What are a number of risk factors for increase perinatal mortality in dizygotic twins?

Answer 7

• genetics (African decent)
• BMI
• maternal age

Question 8

Is the risk of developing morbidities such as cerebral palsy higher in single pregnancy or multiple pregnancy n dizygotic twins?

Answer 8

• multiple pregnancy

Question 9

What is a stillbirth?

Answer 9

• baby dies in the womb after 20 weeks

Question 10

A stillbirth is when a baby dies in the womb after 20 weeks. Does the risk of stillbirth increase with the number of multiple pregnancy?

Answer 10

• increases as number of multiple pregnancy increases
• singleton 6-8/1000 births
• twins 37/1000
• triplets 52/1000
• > 3 pregnancy 231/1000

Question 11

In a women with multiple pregnancy the risk of morbidities such as neurological disorders such as cerebral palsy increases as the number of pregnancies increases. What are the 2 main reasons identified for this increase in morbidities with multiple pregnancy?

1 - high BMI and lower birth weight
2 - high BMI and premature births
3 - lower birth weight and premature birth
4 - lower birth weight and low BMI

Answer 11

3 - lower birth weight and premature birth

Question 12

What does zygosity refer to?

Answer 12

• the genetic make up of a pregnancy

- in twins, this can be mono or dizygotic

Question 13

What does mono and dizygotic mean?

Answer 13

• mono = 1 egg and 1 sperm form a zygote which then splits into 2 separate groups of cells
• di = 2 eggs and 2 sperm form seperate zygotes

Question 14

What does chorionicity refer to?

Answer 14

• the chroion is the double layer membrane (trophoblasts) that form the placenta
• chorionicity refers to the number of placenta that are present

Question 15

Chorionicity refers to the number of placenta present during pregnancy. What do mono and di-chorionic refer to?

Answer 15

• monochorionic = 1 placenta is shared

- dichorionic = there are 2 separate placenta

Question 16

What does amnionicity refer to?

Answer 16

• the amniotic sacs that a foetus develops within

Question 17

Amnionicity refers to the amniotic sacs that a foetus develops within. What does mono and diamniotic refer to?

Answer 17

• monoamniotic = foetus share the same amniotic sac

- dioamnioitc = foetus have their own individual amniotic sacs

Question 18

Dizygotic twins are where there are 2 separate eggs and each gets fertilised by a separate sperm, forming 2 separate zygotes. Which of the following are dizygotic twins able to become:

1 - dichorionic monoamniotic
2 - dichorionic diamniotic
3 - monochorionic monoamniotic
4 - monochorionic diamniotic

Answer 18

2 - dichorionic diamniotic

- everything is separate so there will be 2 of everything

Question 19

In monozygotic pregnancies we need to be aware of the different types of chorionicity and amnionicity, such as:

• chorionicity = mono or dichorionic
• amnionicity = mono or diamniotic

In a monozygotic pregnancy (identical twins) what types chorionicity and amnionicity can monozygotic twins have?

Answer 19

• dichorionic-diamniotic = separate placenta and amniotic sac
• monochorionic-diamniotic = same placenta BUT separate amniotic sac
• monochorionic-monoamniotic = same placenta and same amniotic sac

Question 20

In monozygotic pregnancies we need to be aware of the different types of chorionicity and amnionicity. Monozygotic twins can be the following:

• dichorionic-diamniotic = separate placenta and amniotic sac
• monochorionic-diamniotic = same placenta BUT separate amniotic sac
• monochorionic-monoamniotic = same placenta and same amniotic sac

What determines which forms of chorionicity and amnionicity monozygotic twins develop into?

Answer 20

• the timing of when the embryonic cells divide

Question 21

In monozygotic pregnancies we need to be aware of the different types of chorionicity and amnionicity. Monozygotic twins can be the following:

• dichorionic-diamniotic = separate placenta and amniotic sac
• monochorionic-diamniotic = same placenta BUT separate amniotic sac
• monochorionic-monoamniotic = same placenta and same amniotic sac

The timing of when the embryonic cells divide determines which forms of chorionicity and amnionicity a monozygotic twins develop into. What are the time points for each of the options above where the cells of the embryo divide?

Answer 21

• dichorionic-diamniotic = 2-3 days
• monochorionic-diamniotic = 3-8 days
• monochorionic-monoamniotic = 8-13 days

Question 22

In monozygotic pregnancies we need to be aware of the different types of chorionicity and amnionicity. Monozygotic twins can be the following:

• dichorionic-diamniotic = separate placenta and amniotic sac
• monochorionic-diamniotic = same placenta BUT separate amniotic sac
• monochorionic-monoamniotic = same placenta and same amniotic sac

The timing of when the embryonic cells divide determines which forms of chorionicity and amnionicity a monozygotic twins develop into. Generally the splitting occurs before 13 days for all 3 variations. However, if there is no splitting, what can this lead to?

Answer 22

• conjoined twins

Question 23

In a diochorionic diamniotic pregnancy how many babies, placentas and amnionic sacs would be present?

1 - 1 baby, 2 placenta, 2 sacs
2 - 2 baby, 1 placenta, 2 sacs
3 - 2 baby, 2 placenta, 2 sacs
4 - 2 baby, 2 placenta, 1 sac

Answer 23

3 - 2 baby, 2 placenta, 2 sacs

Question 24

In a monochorionic diamniotic pregnancy how many babies, placentas and amnionic sacs would be present?

1 - 1 baby, 2 placenta, 2 sacs
2 - 2 baby, 1 placenta, 2 sacs
3 - 2 baby, 2 placenta, 2 sacs
4 - 2 baby, 2 placenta, 1 sac

Answer 24

2 - 2 baby, 1 placenta, 2 sacs

Question 25

In a monochorionic monomniotic pregnancy how many babies, placentas and amnionic sacs would be present? 1 - 2 baby, 1 placenta, 1 sac 2 - 2 baby, 1 placenta, 2 sacs 3 - 2 baby, 2 placenta, 2 sacs 4 - 2 baby, 2 placenta, 1 sac

Answer 25

1 - 2 baby, 1 placenta, 1 sacs

Question 26

In a trichorionic triamniotic pregnancy how many babies, placentas and amnionic sacs would be present? 1 - 3 baby, 1 placenta, 1 sac 2 - 3 baby, 3 placenta, 3 sacs 3 - 3 baby, 2 placenta, 2 sacs 4 - 2 baby, 2 placenta, 1 sac

Answer 26

2 - 3 baby, 3 placenta, 3 sacs

Question 27

In a dichorionic triamniotic pregnancy how many babies, placentas and amnionic sacs would be present? 1 - 3 baby, 1 placenta, 1 sac 2 - 3 baby, 3 placenta, 3 sacs 3 - 3 baby, 2 placenta, 2 sacs 4 - 3 baby, 2 placenta, 3 sac

Answer 27

4 - 3 baby, 2 placenta, 3 sac

Question 28

Are more twins mono or dizygotic?

Answer 28

- monozygotic twins = 1 in 3 | - dizygotic twins = 2 in 3

Question 29

In monozygotic pregnancies we need to be aware of the different types of chorionicity and amnionicity. Monozygotic twins can be the following: - dichorionic-diamniotic = separate placenta and amniotic sac - monochorionic-diamniotic = same placenta BUT separate amniotic sac - monochorionic-monoamniotic = same placenta and same amniotic sac What is the incidence of each of the above 3 scenarios?

Answer 29

- dichorionic-diamniotic = 25% - monochorionic-diamniotic = 75% - monochorionic-monoamniotic = 2%

Question 30

Why is it important to determine the chorionicity (number of placenta) of a multiple pregnancy?

Answer 30

- need to know if a placenta and blood supply are shared | - shared blood supply has implications of adverse outcomes

Question 31

It important to determine the chorionicity (number of placenta) of a multiple pregnancy to determine if the foetus are sharing the same blood supply. What is the optimal time to determine this and what imaging modality if generally used?

Answer 31

- 10-13 weeks | - ultrasound

Question 32

Why is it important to determine the zygosity?

Answer 32

- monozygotes have higher risk of congenital anomalies | - monozygotes have higher risk of still birth and neonatal death

Question 33

In monozygotic pregnancies we need to be aware of the different types of chorionicity and amnionicity. Monozygotic twins can be the following: - dichorionic-diamniotic = separate placenta and amniotic sac - monochorionic-diamniotic = same placenta BUT separate amniotic sac - monochorionic-monoamniotic = same placenta and same amniotic sac Does mono or dichorionic pregnancy generally have a higher associated risk?

Answer 33

- monochorionic (sharing placenta) due to sharing blood supply

Question 34

If a woman is pregnant with a multiple pregnancy, what are some of the most common risks to her whilst pregnant?

Answer 34

- pre-eclampsia (high BP and coagulation) - gestational diabetes - gestational hypertension - anemia - post-partum haemorrhage - caesarean section - death

Question 35

One key foetal risk in a multiple pregnancy is the twin to twin transfusion syndrome. What is this?

Answer 35

- a rare pregnancy condition affecting identical twins or other multiples - occurs in monochorionic (sharing a placenta) twins - there is abnormal sharing of blood vessels where one twin becomes a donor and the other twin becomes a recipient

Question 36

One key foetal risk in a multiple pregnancy is the twin to twin transfusion syndrome. This is a rare pregnancy condition affecting identical twins or other multiples and occurs in monochorionic (sharing a placenta) twins. There is abnormal sharing of blood vessels where one twin becomes a donor and the other twin becomes a recipient. Why can this be dangerous?

Answer 36

- the donor does not develop as quickly and could die | - the recipient will be larger and develop quicker

Question 37

One key foetal risk in a multiple pregnancy is the twin to twin transfusion syndrome. This is a rare pregnancy condition affecting identical twins or other multiples and occurs in monochorionic (sharing a placenta) twins. There is abnormal sharing of blood vessels where one twin becomes a donor and the other twin becomes a recipient. This can this be dangerous because the donor does not develop as quickly and could die and the recipient will be larger and develop quicker. How can this be treated effectively?

Answer 37

- abnormal blood vessels or anastomosis will be laser ablated

Question 38

Are women who have multiple pregnancy more or less at risk of going into early labour and delivering prematurely?

Answer 38

- increased risk - twin pregnancies = 60% deliver <37 weeks (premature) - triplet pregnancies = 75% deliver <35 weeks (premature)

Question 39

Generally when do dichorionic-diamniotic (2 placenta and 2 amniotic sacs) twins deliver? 1 - <37 weeks 2 - 37 weeks 3 - <35 weeks 4 - >37 weeks

Answer 39

2 - 37 weeks | - anything beyond 37 weeks is associated with death

Question 40

Generally when do monochorionic-diamniotic (1 placenta and 2 amniotic sacs) twins deliver? 1 - 36 weeks 2 - 37 weeks 3 - <35 weeks 4 - >37 weeks

Answer 40

- 36 weeks | - anything beyond 36 weeks is associated with death

Question 41

Generally when do monochorionic-monoamniotic (2 placenta and 2 amniotic sacs) twins deliver? 1 - 36 weeks 2 - 37 weeks 3 - <35 weeks (32-34) 4 - >37 weeks

Answer 41

3 - <35 weeks (32-34) - babies generally get admitted to NICU - beyond 33+6 weeks is associated with increased risk of fetal death

Question 42

For each of the following, what are the delivery options? - dichorionic-diamniotic - monochorionic-diamniotic - monochorionic-monoamniotic

Answer 42

- dichorionic-diamniotic = vaginal or caesarean (depends on presentation) - monochorionic-diamniotic = vaginal or caesarean (depends on presentation) - monochorionic-monoamniotic = caesarean

Question 43

Chorionicity in twins is best and most accurately determined at: ``` 1 - 6-8 weeks of gestation 2 - 6-12 weeks of gestation 3 - 12-14 weeks of gestation 4 - 16-20 weeks of gestation 5 - 30 weeks of gestation ```

Answer 43

3 - 12-14 weeks of gestation (10-13 weeks is optimal)

Question 44

The majority of monozygotic twins will result in a monochorionic pregnancy with one placenta? 1 - True 2 - False

Answer 44

1 - True

Question 45

Cleavage of monozygotic twins between days 4 and 8 will result in a monochorionic monoamniotic pregnancy: 1 - True 2 - False

Answer 45

2 - False | - days 4-8 cleavage will form monochorionic diamniotic