Multiple Pregnancies

Question 1

What is the embryological distinction of twins? What do doctors think about?

Answer 1

Chorionicity and Amnionicity are important, Zygosity with mono/dizygotic only important for DC/DA

• 1 in 70 in Aus twins - 1/3 monozygotic, 2/3 dizygotic, natural twinning 1 in 80.
  
  • DC and DA - dichorionic and diamniotic, day 3-7
  • MC, DA (commonest of monozygotic 2/3)
  • MCMA - mo mo - 1%
  • later day 14 is conjoined.
• DC - lowest risk
• monochorionic - single placental mass

Question 2

What is a general overview of complications of monochorionic twins?

Answer 2

• only one gets TTTS (twin twin transfusion syndrome)
  
  • • TRAPS (twin reversed arterial perfusion syndrome)
      
      • one twin doesn’t have head/heart - become saporophytic of placenta, cause CF in other.
  • TOPS
  • TAPS (twin anaemia polycythaemia sequence)
    growth restriction
• FDIU
• increase preterm birth
• NEC
• IVH (intraventricular haemorrhage)
• ADHD highest concordance

Question 3

Talk about some epidemiology related to problems and situations where you can have twins?

Answer 3

• IVF - >90% from spontaneous conception + ovulation induction.
• causes preterm birth - important to avoid multiple pregnancy.

Question 4

What are some differences with Prenatal testing in twins?

Answer 4

• CFTS - combined first trimester screening
  
  • mainstay of downs syndrome screening
  • for trisome 21
    
    • tests have different sensitivity which is less in twins
    • biochemical findings is useless
• NIPS - non-invasive prenatal screening
  
  • can do NIPS regardless. 99% singleton, 97% twins, small false neg rate.
  • mircoscopic fragments released into fetal circulation
• CVS
  • 10-13 weeks - not good in twins due to double sampling risk 1% miscarriage 2% risk double sampling
• Amniocentesis
  
  • 0.5% risk miscarriage
  • decreased risk of double sampling
• lose standard clinical tools - moving? measure fundal height?
  
  • basic tests unreliable - 1 baby, 2 over one side.
• timing and method of delivery:
  
  • DC at 38wk mark
  • MC at 37wks
• support services

Question 5

What are some routine care steps that can be taken in twins?

Answer 5

• determine gestational age and chorionicity ASAP
  
  • use largest baby to estimate age
• provide info (counsel risks)
  
  • increased demands on mother - back, sleep, toilet, aches, emotional strain.
• nutritional advice
  
  • weight gain - inadequate weight gain associated with preterm birth. BMI specific. More with lower BMI.
• monitor complications

Question 6

What are some maternal complications you should monitor for in twins?

Answer 6

• maternal
  
  • pre-eclampsia (30% in primigavida twin pregnancy)
    
    • aspirin 100mg daily from 12-36weeks
  • gestational DM
    
    • 2x increased risk
    • PCOS and DZ twins
    • OGTT in all multiples (14weeks high risk, 26weeks all)
  • APH - increase mass in placenta
  • PPH 4x rick increase due to increased uterine distension
  • anaemia - 3x risk increase (iron + folate deficiency)
  • Depression
    
    • antenatal
    • postnatal
    • marital disharmony

Question 7

What are some fetal complications you should monitor for?

Answer 7

• DZ fetal anomalies are the same as singletons
  
  • MZ = 3x risk
• growth issues
  
  • mean birthweight
  • perinatal mortality
• prevent preterm delivery
  
  • primary (smoking, treat bacteriuria)
  • secondary (progesterone (debated))
• timing of delivery
  
  • DC DA 37 weeks - late deeaths due to fetal growth
  • MC MA 32 weeks - abnormal CTG after 26weeks
  • MC DA 36wekks - due to TTTS
• mode of delivery - no change in outcomes - c-section from second after first. Second always does a little bit worse.
  
  • after 1st check longitudinal lie of 2nd
  • restart syntocinon - uterus becomes more atonic
  • ARM at pelvic brin

Question 8

What are extra things you should consider in monochorionic twins?

Answer 8

• single fetal intrauterine death (FDIU) concern​
  
  • After 1st trimester, most <24weeks. earlier delivery - between 36-40weeks peak
  • Scan more often. Get out.
  • what happens to one impacts other - exanguinate into cotwin. 15% cotwin death from this. 15% risk of major neurological abnormality (CP/wheelchair).
  • Treatment: - cord ligation, prevents exanguination of other baby
• TTTS (twin twin transfusion syndrome).
  
  • discordance between anastamoses of placental circulation of 2 fetuses. AV anastomoses - artery go into other fetuses vein.
  • 2 Types: (can overlap)
    
    • liquid volume - TOPS - twin oligohydraminos polyhydramnios sequence - vessels with fluid volume shifts. Fluid deplete or overloaded. Renal output decreases in one and increases in the other.
      
      • treatment:
        
        • termination
        • Laser to placenta
        • amniodrainage
      • staging based on oligo, bladder, dopplers, hydrops, death (1-5).
      • MC, polyhydramnios in 1, oligohydramnios other. No other explanation: Duodenal atresia, Oesophageal atresia. etc..
    • TAPS - twin anaemia and polycythaemia sequence. Vessels smaller - volume shifts subtle. Anaemia of one, donor, other becomes receipients.
      
      • Diagnosis: MCA peak systolic velocity, placenta echogenicity
• Selective IUGR
  
  • ​healthy baby to restricted babies. Bit from other hang on for longer.
  • can type them. Different outcomes.
  • Hard to predict when they fall off the purch.
  • Treatment:
    
    • early delivery
    • selective feticide

Question 9

What Management for FDIU for a single baby in twins?

Answer 9

1. Prevention
   
   • threshold delivery
   • cord ligation prevent exanguination
2. surveillance for anaemia
   
   • MCA
   • more often scans
3. Brain imaging
   
   • brain imaging - depending on gestation and brain abnormality.

Question 10

Monoamniotic twins complications?

Answer 10

• cord entanglement (morton’s jelly stops kinks).
• Fetal death
  
  • cord
  • acute TTTS
• Policy of delivering at 32weeks. CTG 3x a day from 25weeks.
• Steroids.
• pump twin - tissue masses - CF, polyhydramnios
• conjoined twins rare