multiple pregnancy

Question 1

zygosity

Answer 1

monozygotic = identical twins from the fertilisation and division of one egg
dizygotic = originating from the fertilisation and development of two eggs ie fraternal twins

Question 2

chorionicity

Answer 2

monochorionic or dichorionic
dizygotic twins are always DCDA
monozygotic twins may be
DCDA if the fertilised egg splits in the first 3 days after fertilization
MCDA if the split occurs day 4-8
MCMA if the split occurs day 8+ (the chorion and amnion have already differentiated)

Question 3

vanishing twin

Answer 3

one twin is lost or vanishes 10-40% of all IVF twin pregnancies
first trimester demise of DCD twin has no negative effect on the surviving twin
can affect NIPT result
2nd and 3rd trimester demine can have serious adverse effect

Question 4

management of DCDA twins

Answer 4

antenatal visits
4 weekly until 28 weeks gestation
2 weekly until 34 weeks gestation
weekly from 34 weeks

offer referral to dietitian (increased caloric, protein, mineral, vitamin intake)
twice daily iron and folic acid (iron deficiency anaemia is associated with pre-term delivery)
multivitamin

Question 5

what criteria do DCDA twins have to meet for vaginal delivery

Answer 5

twins must be diamniotic
twin 1 is cephalic
twin 2 is not >500g heavier than twin 1
neither twin has any evidence of fetal compromise requiring c/s

Question 6

epidural use in delivery of twins

Answer 6

epidural is recommended due to increased risk of operative delivery in twin births and the possibility of intrauterine manipulation of twin two

Question 7

intrapartum care during delivery of DCDA twins

Answer 7

alert senior staff
IVC (increased risk of intrapartum and PPH)
bloods: FBC, G+H, xmatch
continuous CTG
oxytocin infusion is available after birth of twin 1 in case uterine inertia occurs between twin births

Question 8

delivery of the 2nd twin

Answer 8

perform abdominal palpation and vaginal examination immediately after the birth of twin one
monitor FHR continuously
confirm fetal presentation by portable US as required
external cephalic versionn or internal manipulation may be required for malpresentation
perform ARM once fetal presentation is confirmed

Question 9

how quickly should twin 2 be delivered

Answer 9

an to deliver within 30 minutes of twin 1

Question 10

MCDA twin complications

Answer 10

1. twin-twin transfusion synrome TTTS
2. selective intrauterine growth restriction
3. death of one twin
4. twin reversed arterial perfusion sequnece TRAPS

Question 11

TTTS

Answer 11

twin-twin transfusion syndrome
occurs as a result of many or large AV anastomoses deep in the placenta
cardinal prenatal finding is discordant amniotic fluid levels

Question 12

two types of TTTS

Answer 12

1. Twin oligohydramnios/polyhydramnios sequence TOPS
2. Twin anaemia/polycythemia sequence TAPS

Question 13

TTTS management

Answer 13

early referral to a tertiary centre
laser ablation of vascular connections

Question 14

death of one twin in monochorionic pair

Answer 14

death of one twin in a monochorionic pair may result in the death or neurological disability in the survivor

Question 15

twin reversed arterial perfusion sequence TRAPS

Answer 15

surviving twin continues to perfuse the deceased twins’ body via placental anastomoses following first trimester demise
rare complication

Question 16

MCDA twins delivery

Answer 16

monochorionic twins have aa higher rate of still birth
recommend delivery by 37 weeks
vaginal delivery is not contraindicated