15. Multiple pregnancies

Question 1

Aetiology

Answer 1

Ethnicity
Increasing maternal age
Increasing parity
Family history
Fertility treatment

All factors for ‘super ovulation’

Question 2

Zygosity

Answer 2

Monozygous = 1 egg = identical (1/3)

Dizygous = 2 eggs = nonidentical (2/3)

Question 3

Dizygotic twins

Answer 3

2/3 of all twins
seperate amnions, chorionsand placentae
DCDA

Question 4

Monozygotic twins- MCDA

Answer 4

1/3
Splitting at 2 cell stage (1:3)
Splitting in early blastocyst (4 days after formulation, inner cell mass, forms part of embryo) yields 2 inner cell masses
Get common chorion, separate amnions and joined placentae - MCDA

Question 5

Monozygotic twins - MCMA

Answer 5

Later splitting yields 2 embryos from one inner cell mass

Common chorion, amnion, and joined placentae - MCMA

Question 6

Dichorionic

Answer 6

All dizygous twins are dichorionic
Dichorionic twins must be diamniotic
Dichorionic = separate circulations
1:3 monozygous twins are dichorionic

Question 7

Monochorionic

Answer 7

Monozygous twins may be monochorionic (2/3) or dichorionic
MC have vascularly joined placentae
MC twins 3x increased loss rate
MC twins usually diamniotic

Question 8

Diagnosis

Answer 8

Uterine size
Up to 50% at delivery worldwide
Ultrasound

Question 9

Complications of multiple pregnancies

Answer 9

“Everything except post-dates”
Symptoms of pregnancy
Anaemia 
Hypertension 
Intrauterine growth restriction
Pre-term labour
Delivery problems 
Perinatal mortality

Question 10

Mortality of twin pregnancy

Answer 10

Stillbirth – after 24 weeks
Early neonatal – first 7 days
Neonatal – in first 28 days
Perinatal – SB + early neonatal
Infant – first year
Rates are per 1000 births

Question 11

Twin pregnancy - first trimester management

Answer 11

Discuss screening for chromosomal anomalies
Determine chorionicity
Discuss fetal reduction if triplets or more

Question 12

Twin pregnancy - second trimester management

Answer 12

Detection of fetal abnormality
Serial scans for growth for all
DC monthly from 24 weeks
Serial scans for TTTS if MC twins
2 weekly 16-28 weeks then monthly
Maternal complications

Question 13

Monochorionic twins

Answer 13

More fetal malformation
More fetal growth restriction
Twin to twin transfusion

Question 14

Twin twin transfusion syndrome

Answer 14

Abnormal shunting of blood - one baby gets more blood and one gets less - unbalanced anastomosis so one baby (donor twin) ends up with more than the other (recipient twin)
dangerous for both twins because one baby is not getting enough blood, while the one getting too much blood can go into heart failure.
Treated by laser, but this is invasive so has significant risk

Question 15

Twin to twin transfusion

Answer 15

Unbalanced placental vascular anastamoses 
Donor smaller, decreased liquor
High mortality (esp recipient)
Rx - laser or amnio-reduction
Early delivery by caesarean

Question 16

Twin pregnancy - third trimester management

Answer 16

Scanning as in 2nd trimester
Monitor blood pressure
Pre-term labour
Delivery planning

Question 17

Third trimester delivery planning

Answer 17

37-38 weeks for DC twins
vaginal birth or caesarean
Presentation of twin I
36-37 weeks for MC twins
?all MC twins by caesarean?
Pregnancy complications

Question 18

Labour management

Answer 18

Monitoring both twins
Problems delivering twin II
Risk of postpartum bleed

Question 19

Puerperium

Answer 19

Feeding difficulties

Emotional & social support

Question 20

Higher order multiples

Answer 20

Consider fetal reduction
Determine chorionicity
High risk of preterm labour
Deliver preterm by caesarean
Postpartum haemorrhage
Difficult puerperium & after