BACKGROUND AND PURPOSE:

• Aviram et al. (AJOG, 2019) determined the incidence, risk factors, and outcomes for combined twin deliveries (Twin A: vaginal | Twin B: Cesarean)

METHODS:

• Secondary analysis of a prospective, randomized, controlled trial
  • Data derived from the Twin Birth Study (TBS) RCT that compared planned vaginal delivery to planned combined delivery in twin pregnancies
• Participants
  • Twin gestation
  • Between 32w0d and 38w6d
  • First twin vertex
• Groups
  • Planned cesarean delivery
  • Planned vaginal delivery
• Study design and data analysis
  • Comparison of women with combined vs vaginal delivery of both twins
• Primary outcome
  • Risk factors for combined twin deliveries
• Secondary outcomes
  • Rate of perinatal mortality and morbidity

RESULTS:

• 842 women delivered twin A vaginally
  • Combined delivery: 7%
• Women in the combined delivery group had
  • A lower rate of nulliparity (P = 0.047)
    • 22.0% vs 34.7%
  • Twin B: Higher rates of noncephalic presentation at delivery (P < 0.001)
    • 61.0% vs 27.3%
  • Twin B: Higher rates of spontaneous change in presentation from the time of randomization to the time of delivery (P < 0.0001)
    • 72.9% vs 44.3%
• Transverse/oblique lie of twin B following delivery of twin A was associated with risk of combined delivery
  • Adjusted odds ratio (OR) 47.7 (95% CI, 15.4 to 124.5)
• Comparing the combined delivery group to the group where both twins delivered vaginally, the frequency of adverse events in Twin B was significantly increased  
  • Fetal/neonatal death or serious neonatal morbidity
    • 13.6% vs 2.3% (P<0.001)
  • 5-minute Apgar score <7
    • 20.7% vs 2.1% (P<0.001)
  • NICU admission ≥48 hours
    • 12.07% vs 5.27% (P<0.001)
  • Abnormal level of consciousness (coma)
    • Coma 1.72% vs 0% (P =0.02)
  • Assisted ventilation ≥24 hours
    • 5.17% vs 0.90% (P<0.001)

CONCLUSION:

• This study confirmed increased risk for combined delivery for twin B (e.g. mortality, morbidity, NICU admission, etc.)
• The only risk factor for combined delivery following adjustment for confounding was transverse/oblique lie (not breech) of twin B following vaginal delivery of twin A
• There was no association between adverse outcome in twin B and initial presentation of twin B or with inter-twin delivery interval
• The authors suggest these results may have clinical implications including a discussion regarding “the policy of routine ‘double set-up’ for twin deliveries in the operating room, as a way to decrease the decision-to-incision interval”
• Authors acknowledge limitations including the fact that the original TBS study was not powered for this study’s subanalysis

Learn More – Primary Sources:

The worst of both worlds—combined deliveries in twin gestations: a subanalysis of the Twin Birth Study, a randomized, controlled, prospective study

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