FRCA Notes

Multiple Pregnancy

This hasn't been a CRQ or SAQ, to my knowledge, but is mentioned explicitly in the intermediate curriculum: 'discusses the obstetric and anaesthetic management of multiple pregnancy'

Resources

  • Twins occur in 0.4% (monozygotic) to 1.4% (dizygotic) of pregnancies
  • The incidence increases with increasing maternal age, increasing parity or use of assisted conception
  • Multiple gestation pregnancies carry increased risk of maternal and foetal complications, and provide challenging physiological and logistical factors for the anaesthetist

Respiratory

  • FRC and TLC further reduced
  • ↑ tendency to hypoxia
  • ↑ incidence difficult intubation
  • ↑ minute ventilation (due to higher progesterone levels)

Cardiovascular

  • Extra 400-500ml blood volume
  • Relative anaemia therefore more common
  • Greater effects from aortocaval compression
  • Increased HR, SV, contractility and cardiac index
  • Decreased cardiac reserve and may have profound hypotensive response to anaesthesia (RA or GA)

Neurological

  • Greater epidural space vascularity
  • Greater sensitivity to LA (due to higher progesterone levels)
  • Historically though to required reduced doses of intrathecal LA due to greater spread, although some suspicion this may not be the case

Gastrointestinal

  • Worse LOS incompetence
  • Increased maternal weight

Maternal

  • The risk of most maternal complications is increased
  • Maternal complications increase with the number of foetuses carried
Complication Notes
↑ UTI
↑ Hyperemesis gravidarum
↑ GDM
↑ Risk of PET and HELLP 2 - 4x increase (to 9.5%); patients should be given aspirin
↑ Rate of APH Due to placental abruption (2 - 3x) or placenta praevia (40% ↑ risk)
↑ Need for LSCS
↑ Rate of PPH Up to 12%, usually due to atony
Normal EBL in vaginal twin delivery 900ml
↑ Maternal mortality Up to 3x increase

Foetal

Increased complications
Premature birth (up to 50%)
↑ vasa praevia
IUGR or discordant growth
Congenital abnormalities (~2x)
Twin-twin transfusion syndrome (up to 10%)
IUFD
Perinatal mortality (7x)


  • Twin gestation alone is not an indication for LSCS; may be delivered vaginally although triplets or higher order gestations require caesarean section
  • Contraindications to attempted vaginal delivery include:
    • Monoamniotic twins
    • Presenting twin not in cephalic position
    • Higher order gestations i.e. triplets etc.
  • Delivery should be planned for certain gestation depending on type of twin:
Type Planned delivery date
DCDA 38 - 39 weeks
MCDA 34 - 36 weeks
MCMA 32 - 34 weeks

Elective LSCS

  • Regional anaesthesia is preferred and associated with better 2nd twin outcome
  • Upright positioning may be more difficult and require a lateral approach

  • Increased risk of hypotension from aortocaval compression
  • Lateral position may be required rather than simple tilt

  • Higher PPH risk should prompt:
    • 2 wide-bore IV access from the start
    • XM'd blood
    • Use of cell salvage

  • Higher risk of post-operative pulmonary oedema due to higher volume of placental autotransfusion

Labour & vaginal delivery

  • Risks of vaginal delivery should be discussed antenatally

  • Early epidural analgesia should be advised, facilitating extension to surgical anaesthesia in case of emergency
  • Early neuraxial intervention is associated with:
    • Better pain control
    • Greater pelvic muscle relaxation
    • Inhibition of premature maternal expulsive efforts

  • Many centres perform delivery in theatre in case of need for urgent intervention
    • 27% of twin pregnancies require anaesthetic intervention
    • 6% require LSCS for delivery of 2nd twin
  • Typically 15 - 30mins is allowed for delivery of the 2nd twin after delivery of the first