Multiple Births Flashcards

1
Q

What is the rate of twin births compared to triplet births?

A

About 30 per 1000 births are twins, while about 1 per 1000 births are triplets.

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2
Q

What are the two types of twin births?

A

Twin births can be identical (monozygotic), arising from a single fertilized egg (zygote), or non-identical (dizygotic), arising from two separate eggs.

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3
Q

How does the rate of non-identical twinning vary across different communities?

A

The rate of non-identical twinning varies from 10 to 40 per 1000 in different communities.

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4
Q

What factors increase the risk of non-identical twinning in women?

A

The risk of non-identical twinning increases in women over 35 years of age and in women receiving infertility treatment, as they both have a higher rate of polyovulation

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5
Q

What is the incidence of identical twins in all communities?

A

The incidence of identical twins is about 3 per 1000 births in all communities.

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6
Q

Do non-identical twins share the same placenta?

A

No, non-identical twins always have separate placentas.

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7
Q

What term describes the placentas of non-identical twins?

A

The placentas of non-identical twins are called dichorionic, as each placenta has its own chorion.

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8
Q

Can twin-to-twin shunts occur between dichorionic placentas?

A

No, there are never anastomoses between dichorionic placentas, so twin-to-twin shunts cannot occur.

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9
Q

What percentage of identical twins share a single placenta?

A

70% of identical twins share a single placenta, known as monochorionic placentas.

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10
Q

How is the type of placentation in identical twins determined?

A

The timing of the zygote split determines the type of placentation, with an early split resulting in dichorionic placentas.

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11
Q

What is the significance of dichorionic placentas in determining zygosity in twins?

A

With dichorionic placentas, the twins must be non-identical if one twin is male and the other female. However, about 30% of same-sex twins with dichorionic placentas will be identical, necessitating DNA testing for confirmation.

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12
Q

How is chorionicity determined in twins?

A

Chorionicity can be diagnosed by ultrasonography at 12 weeks of gestation. Thick dividing chorions indicate dichorionic placentas, while the absence of a chorion separating the placentas indicates identical twins.

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13
Q

What are the characteristics of a monochorionic placenta?

A

A monochorionic placenta usually has two amnions (monochorionic-diamniotic). If both twins are in a single amniotic sac (monochorionic-monoamniotic), there is an increased risk of umbilical cord entanglement and conjoint twinning.

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14
Q

Why are twins with a monochorionic placenta at risk of twin-to-twin transfusions?

A

Twins with a monochorionic placenta always have anastomoses and share the same blood pool, allowing for twin-to-twin transfusions.

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15
Q

How is chorionicity determined after delivery?

A

Chorionicity can be easily determined by examining the placenta after delivery.

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16
Q

What percentage of twins and triplets are born preterm?

A

50% of twins and 90% of triplets are born preterm.

17
Q

What is the risk of major congenital abnormalities in identical twins compared to non-identical twins?

A

The risk of major congenital abnormalities is increased to 6% in identical twins, whereas it is only 3% in non-identical twins, which is the same risk as singletons.

18
Q

Why is the risk of major congenital abnormalities higher in identical twins?

A

The higher risk in identical twins is attributed to monozygotic twinning, which is an abnormal event due to the splitting of a single zygote.

19
Q

What is the cause of growth restriction in twins?

A

Growth restriction in twins is common due to the increased nutritional demand by two fetuses.

20
Q

What is twin-to-twin transfusion syndrome (TTTS)?

A

Twin-to-twin transfusion syndrome (TTTS) occurs in monochorionic twins and results in a larger polycythaemic twin with polyhydramnios, who is the blood recipient, and a smaller anaemic twin with oligohydramnios, who is the blood donor.

21
Q

How does TTTS differ in monochorionic and dichorionic twins?

A

In monochorionic twins, TTTS occurs due to twin-to-twin anastomoses, resulting in one twin becoming larger and the other smaller. In contrast, in dichorionic twins, there are no anastomoses, and the smaller, growth-restricted twin may have polycythaemia due to chronic hypoxia.

22
Q

effects of polyhydramnios

A

heart failure due to fluid overload

23
Q

What are some factors contributing to higher neonatal mortality and morbidity in multiple pregnancies?

A

Neonatal mortality and morbidity are higher in multiple pregnancies due to prematurity, growth restriction, congenital abnormalities, and complicated deliveries.

24
Q

Why is it important to deliver twins in a hospital with facilities for newborn care?

A

Delivering twins in a hospital with newborn care facilities is crucial due to the higher risks associated with multiple pregnancies, ensuring prompt medical intervention if needed.

25
Q

What challenges do parents of twins face in terms of breastfeeding and bonding?

A

Parents of twins may face challenges in breastfeeding and bonding with two or more infants simultaneously, requiring additional support and resources.