Multiple pregnancies

Question 1

What is the incidence of multiple pregnancy?

Answer 1

2-7% in far east, 9-20% Europe, 2-45% Nigeria

• Geographic variation suggests genetic component. Superovulation/FH of twins as extra evidence
• At an advantage if perinatal and infant loss rates high
• Incidence of multiple births may be due to age and IVF

Question 2

Suggest 5 factors that may be implicated in ‘superovulation’

Answer 2

1. Ethnicity
2. Increased maternal age
3. Increased parity
4. Family history
5. Fertility treatment

Question 3

There are 2 factors important to consider in multiple pregnancy.

ZYGOSITY
Define it.

Answer 3

Zygosity describes the level of similarity between the alleles in an organism.

Question 4

There are 2 factors important to consider in multiple pregnancy.

ZYGOSITY
Discuss Dizygous twins

Answer 4

Dizygous- 2 eggs fertilised= non identical twins

• 2/3 of twins
• Seperate amnions, chorions and placentae
• DCDA (Dichorionic diamniotic twin pregnancy)

Question 5

There are 2 factors important to consider in multiple pregnancy.

ZYGOSITY
Discuss Monozygous twins

Answer 5

Monozygous - 1 egg fertilised = identical twins

1. Splitting very early in blastocyst yields 2 inner cell masses (24 hours post fertilisation)
   - Share a common chorion, seperate amnions and “joined” placentae
   - MCDA (monochorionic diamniotic)
2. Late splitting yields two embryos from one inner cell mass
   - Share chorion, amnion and “joined” placentae
   - MCMA (monochorionic, monoamniotic)

Question 6

There are 2 factors important to consider in multiple pregnancy.

CHORIONICITY
Define it.

Answer 6

Number or placentas/sac

Question 7

There are 2 factors important to consider in multiple pregnancy.

CHORIONICITY
How does it vary between monozygous and dizygous twins

Answer 7

1. All dizygous twins are dichorionic (they have seperate circulations). Dichorionic twins must by diamniotic.
2. Monozygous twins may be monochorionic (2/3) or dichorionic (1/3)
   - MC have vascularly joined placenta
   - MC twins 3x increased loss rate
   - MC twins usually diamniotic

Question 8

How do you diagnose multiple pregnancies?

Answer 8

• Uterine size
• Ultrasound

** Up to 50% discovered at birth worldwide

Question 9

State 5 possible complications of multiple pregnancies

Answer 9

1. “Everything except post-dates”- complications more common
2. Symptoms of pregnancy
3. Anaemia
4. Hypertension
5. Intrauterine growth restriction
6. Pre-term labour
7. Delivery problems perinatal mortality

Question 10

How does the rate of stillbirths, perinatal, neonatal and infant death vary with multiple pregnancy

Answer 10

Increase as number of embryos increase

Question 11

How do you manage multiple pregnancies?

Answer 11

• During the first trimester discuss screening for chromosomal anomalies , determine chorionicity and discuss fetal reduction if triplets or more
• During second trimester detect any fetal abnormalities, serial scans for growth for all. Serial scanns for TTTS if MC twins, monthly from 24 weeks if DC
• During third trimester repeat 2nd trimester scanning, monitor BP, be cautious or pre-term labour, delivery planning

Any maternal complications?

Question 12

Why might you exercise more caution when dealing with monochorionic twin pregnancy?

Answer 12

More fetal malformation, more fetal growith restriction and twin-twin fusion

• unbalanced placental vascular anastomoses
• donor smaller, decreased liquor
• high mortality
• Rx- laser or amnio-reduction
• early delivery by c-section
• unidirectional AV- shunt in twin-twin transfusion

Question 13

How does delivery planning differ between DC and MC twins?

Answer 13

DC twins at 37-38 weeks by vaginal birth or c-section

MC twins at 36-37 weeks by c-section

Question 14

Discuss labour management in the case of twins

What is puerperium and what are effects?

Answer 14

• Monitor both twins, any problems delivering twin 2?
• Risk of postpartum bleed

Puerperium: the 6 weeks post-partum when the mothers reproductive organs are returning to their non-pregnant state

• feeding difficulties
• require social and emotional support

Question 15

What are the risks of higher order multiples? How would you adjust management?

Answer 15

Rx

• Difficuly peurperium and after
• Postpartum haemorrhage
• Preterm labour

Determine chorionicity, consider fetal reduction and deliver preterm by caesarean