Multiple Births

Question 1

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

Answer 1

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

Question 2

What are the two types of twin births?

Answer 2

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

Question 3

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

Answer 3

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

Question 4

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

Answer 4

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

Question 5

What is the incidence of identical twins in all communities?

Answer 5

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

Question 6

Do non-identical twins share the same placenta?

Answer 6

No, non-identical twins always have separate placentas.

Question 7

What term describes the placentas of non-identical twins?

Answer 7

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

Question 8

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

Answer 8

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

Question 9

What percentage of identical twins share a single placenta?

Answer 9

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

Question 10

How is the type of placentation in identical twins determined?

Answer 10

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

Question 11

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

Answer 11

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.

Question 12

How is chorionicity determined in twins?

Answer 12

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.

Question 13

What are the characteristics of a monochorionic placenta?

Answer 13

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.

Question 14

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

Answer 14

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

Question 15

How is chorionicity determined after delivery?

Answer 15

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

Question 16

What percentage of twins and triplets are born preterm?

Answer 16

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

Question 17

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

Answer 17

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.

Question 18

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

Answer 18

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

Question 19

What is the cause of growth restriction in twins?

Answer 19

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

Question 20

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

Answer 20

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.

Question 21

How does TTTS differ in monochorionic and dichorionic twins?

Answer 21

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.

Question 22

effects of polyhydramnios

Answer 22

heart failure due to fluid overload

Question 23

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

Answer 23

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

Question 24

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

Answer 24

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.

Question 25

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

Answer 25

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