Twin Pregnancy Flashcards

1
Q

Natural rate of twinning

A

1:90

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2
Q

Incidence of dizygotic twins increases with….

A
Age
Parity
Weight 
Height
Higher in some families
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3
Q

Multiple pregnancies is suspected in…

A
Large for date uterine size
Multiple foetal HRs detected
Multiple foetal parts felt
HCG and maternal serum alpha-fetoprotein is elevated for gestational age
Pregnancy with ART
]
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4
Q

If multiple pregnancy is suspected, how is this confirmed?

A

USS

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5
Q

What does ART mean?

A

Assisted reproduction technique

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6
Q

Two types of twin zygosity

A

Monozygotic

Dizygotic

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7
Q

What % of twins are dizygotic?

A

70-80%

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8
Q

How do you get dizygotic twins?

A

Fertilisation of two ova

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9
Q

What % of twins are monozygotic?

A

20-30%

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10
Q

How do you get monozygotic twins?

A

Result from cleavage of a single fertilised ova

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11
Q

In monozygotic twins, what determines placentation?

A

The timing of cleavage

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12
Q

In dichorionic/diamniotic monozygotic twins, when did cleavage occur?

A

In the first 3 days after fertilisation

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13
Q

What type of monozygotic twins has the lowest mortality rate of all the monozygotic twins?

A

Dichorionic/diamniotic

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14
Q

What surrounds dichorionic/diamniotic monozygotic twins?

A

Each foetus will be surrounded by an amnion and chorion like dizygotic twins

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15
Q

In monochorionic/diamniotic monozygotic twins, when did cleavage occur?

A

Between day 4 and 8 after fertilisation

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16
Q

Mortality of monochorionic/diamniotic monozygotic twins

A

25%

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17
Q

What covers a monochorionic/diamniotic monozygotic twin?

A

Share single placenta but separate amniotic sac

18
Q

“Chorionic” refers to…

A

Placenta

19
Q

“Amniotic” refers to….

A

Amniotic sac

20
Q

In monochorionic/monoamniotic monozygotic twins, when does cleavage occur?

A

After the 8th day of fertilisation (day 9-12)

21
Q

What causes a monochorionic/monoamniotic monozygotic twin?

A

Share single placenta and single sac

22
Q

How much of monozygotic twins are monochorionic/monoamniotic?

A

<1% of cases

23
Q

Mortality of monochorionic/monoamniotic monozygotic twins

A

mortality 50-60%, usually before 32 weeks

24
Q

For conjoined twins, when does cleavage occur?

A

After day 12

25
Q

Complications of multiple pregnancy

A
high perinatal mortality and morbidity (3-4x higher than singleton)
abortion 
nausea and vomiting
preterm labour (50%)
IUGR
PET (3x higher than singleton)
polyhydramnios in 10% 
Congenital abnormalities
PPH
Placental abruption 
Placental praevia
Discordant twin growth 
Malpresentation 
Cord prolapse
Operative delivery
26
Q

At what gestation are twins delivered at?

A

37 weeks

27
Q

At what gestation are triplets delivered at?

A

33 weeks

28
Q

At what gestation are quadruplets delivered at?

A

29 weeks

29
Q

Causes of perinatal morbidity and morality in twins

A
Prematurity (RDS)
Birth trauma
Cerebral haemorrhage 
Birth asphyxia
Stillbirth 
Congenital anomalies
30
Q

Definition of twin-twin transfusion (TTN)

A

One foetus (in monochorionic twins) donates blood to the other due to vascular anastomoses

31
Q

In twin twin transfusion, what happens to the recipient?

A

Heart failure
Polyhydramnios
Hydrops

32
Q

In twin-twin transfusion, what happens to the donor?

A

IUGR

Oligohydramnios

33
Q

Treatment of twin-twin transfusion

A

Amnio-reduction of recipient twin
Intra-uterine blood transfusion to donor twin
Selective foetal reduction
Fetoscopic laser ablation of placenta anastomoses

34
Q

Antenatal management of multiple pregnancy

A

Adequate nutrition (300 calories per day per foetus)
Prevent anaemia
More frequent antenatal visits
USS
- chronicity at 9-10 weeks
- nuchal translucency at 12-13+ weeks
- assessment of foetal growth and wellbeing at 3-4 weeks from 23 weeks onwards
Multifoetal reduction may be offered for high order multiple gestation in the first trimester
Preterm labour risk
- steroids for foetal lung maturation

35
Q

Preterm labour risk of multiple pregnancy is determined by….

A

Serial cervical length assessment

36
Q

When assessing chronicity, what sign is seen is dichorionic twins?

A

Twin peak sign (lambda)

37
Q

When assessing chorionicity, what sign is seen in monochorionic twins?

A

T sign

38
Q

Labour management in multiple pregnancy

A

If first foetus cephalic = normal delivery
Non-vertex first twin = C section
Locked twins with Breech-vertex = C section
Active management of IIIrd stage to prevent PPH

39
Q

Management of labour in multiple pregnancy depends on….

A

Presentation
Gestational age
Presence of foetal complications
Experience of obstetrician

40
Q

Usually how to deliver the twins if the first foetus is cephalic

A

Normal delivery

41
Q

How to deliver if the first twin is non-vertex

A

C section

42
Q

How to deliver if there are breech-vertex locked twins

A

C section