multiple pregnancy

Question 1

define monochorionic multiple pregnancy?

Answer 1

single placenta is shared by two or more fetuses

Question 2

risk factors for multiple pregnancy?

Answer 2

assisted reproduction, increasing maternal age, increasing parity

Question 3

what do we mean by dizygotic twins?

Answer 3

non-identical twins; two different eggs were fertilised and implanted into uterine wall–> 2 x placenta

Question 4

what do we mean by monozygotic twins?

Answer 4

identical twins- one fertilised egg splits into two and implants into uterine wall

Question 5

what are some maternal complications that we have to consider in multiple pregnancy

Answer 5

pre-eclampsia
gestational diabetes
APH
PPH
anaemia

Question 6

what does TTTS stand for in multiple pregnancy?

Answer 6

twin to twin tranfusion syndrome

Question 7

what does TAPS stand for in multiple pregnancy?

Answer 7

twin anaemia polycythaemia sequence

Question 8

which u/s is best to confirm twinning and their chorionicity and amnionicity?

Answer 8

first trimester u/s

Question 9

in a mother carry dizygotic twins, what is risk of having one child affected by down’s syndrome?

Answer 9

doubled risk bc each twin carries their own risk

Question 10

how might we reduce the risk of pre-eclampsia in a woman carrying multiple pregnancies?

Answer 10

aspirin 100mg/day from 12-36 weeks

Question 11

when might we trial vaginal delivery for a pregnant woman with twins?

Answer 11

if the first twin is in a vertex position may try to do a vaginal delivery, however low threshold for c-section in the case complications arise

Question 12

after ___ weeks gestation, chorionicity in a multiple pregnancy becomes difficult to determine.. fill in the gap

Answer 12

14 weeks’ gestation

Question 13

what is the management of twin to twin transfusion sequence?

Answer 13

Laser ablation of vascular connections is the recommended treatment for the majority of pregnancies with TTTS that require intervention, and referral to a laser surgery facility should be considered - even where this would mean interstate transfer

Early referral is recommended to allow optimal treatment before the onset of severe disease and cervical shortening.

Question 14

what is the risk of delivering term monochorionic monoamionic twins vaginally?

Answer 14

cord entanglement

Question 15

what defines chorionicity and amnionicity in multiple pregnancy?

Answer 15

Chorionicity and amnionicity is determined by timing of zygote cleavage

Question 16

how do we determine the zygosity of a dichorionic multiple pregnancy seen on u/s?

Answer 16

Zygosity can only be reliably determined however if two different genders are seen on u/s

Question 17

what is the sensitivity of combined screening for down’s syndrome for multiple pregnancy?

Answer 17

Down’s syndrome combined screening 75-85% sensitive in twins (U/s is better than maternal serum analytes in this case)

NIPS-> mixed pattern on cell free fetal DNA (but still quite sensitive)

Question 18

what are some antenatal/intrapartum considerations for multiple pregnancy?

Answer 18

• Generally will go into spontaneous preterm labour
• Cervical cerclage +/- progesterone plessaries have NOT been shown to reduce preterm labour
• Advise women to stop smoking, treat asymptomatic bacteriuria
• Administer 100-150mg aspirin daily from < 16 weeks to prevent preeclampsia
• IM celestone +/- magnesium sulfate for neuroprotection in anticipation of preterm labour

Caesarean deliveries are more common than vaginal delivery however vaginal delivery may be possible if presentation appropriate

Question 19

a lady with twins has her 20 week u/s and it shows:
Duodenal atresia- double bubble on u/s
Polyhydramnios
VSD

What are you thinking and what are your management options?

Answer 19

• -> Highly likely that this is T21
• -> amniocentesis for each sac to diagnose T21
• -> option of selective termination–> dependent on chorionicity

If dichorionic–> KCL into the heart –> fetal death in 60% but this leads to increased mortality of the surviving fetus in the early gestation period

Late termination for T21 is preferred at 36 weeks in this case but runs the risk of going into labour before termination can be performed

Question 20

monochorionic twins are always….?

what about dichorionic twins?

Answer 20

monochorionic twins are always monozygotic identical twins

dichorionic twins can either be monozygotic or dizygotic but the chances are higher for dizygotic

Question 21

what are the different chorionicity/amnionicity arrangements for monozygotic twins?

Answer 21

dichorionic diamnionic

monochorionic diamniontic

monochorionic monoamniotic

conjoined twins