BACKGROUND AND PURPOSE:

• Studies investigating the optimal mode of delivery for monochorionic-diamniotic twins are mostly small, retrospective, observational studies
• Aviram et al. (AJOG, 2020) compared perinatal and maternal outcomes of planned cesarean delivery and planned vaginal delivery of monochorionic-diamniotic twins using the Twin Birth Study data

METHODS:

• Secondary analysis of the Twin Birth Study
• Twin Birth Study: RCT that included dichorionic-diamniotic (DCDA) and monochorionic-diamniotic (MCDA) twins from 32w0d to 38w6d
• Participant data used for this secondary analysis
  • MCDA twin pregnancies | Twin A was in cephalic presentation | Each twin had an estimated weight between 1500 and 4000 grams
• Intervention
  • Planned cesarean
  • Planned vaginal delivery
• Study design
  • Elective delivery planned between 37 weeks and 5 to 7 days of gestation and 38 weeks and 6 to 7 days of gestation
• Comparisons in maternal and perinatal outcomes were made between
  • The two intervention groups
  • MCDA and DCDA twin pregnancies

RESULTS:

• Current secondary study
  • Planned cesarean: 346 women
  • Planned vaginal delivery: 324 women
• Rate of cesarean delivery
  • Planned vaginal delivery: 39.2%
  • Planned cesarean delivery: 91.3%
• There was no significant difference in gestational age at delivery between the groups (P = 0.78)
  • Vaginal: 34.4 weeks
  • Cesarean: 34.5 weeks
• There was no difference in maternal outcomes between the two intervention groups
• The rate of adverse neonatal composite outcomes in twins A or twins B was similar in both intervention groups
  • Twins A: 1.2% vs 1.2% (P = 0.92)
  • Twins B: 1.2% vs 3.2% (P = 0.09)
• In the planned cesarean group, the rate of adverse neonatal composite outcome was higher in twins B than twins A (P = 0.03)
  • Twins A: 1.2%
  • Twins B: 3.2%
• When comparing MCDA pregnancies and DCDA pregnancies, there was no difference in the primary adverse neonatal composite outcome between twins A or twins B
  • Twins A: 1.2% vs 1.3% (P = 0.89)
  • Twins B: 2.3% vs 2.7% (P = 0.47)

CONCLUSION:

• For MCDA twin pregnancies (1) between 32 weeks and 38 weeks; (2) between 1500 and 4000 grams and (3) twin A is in cephalic presentation, planned cesarean delivery did not impact the risk of serious adverse neonatal outcomes compared to vaginal delivery
• There is a significant limitation to this study as it was underpowered for the primary composite outcome | However, it is unlikely an RCT will be planned for this specific twin subgroup due to number of participants required for higher power (>6000)
• The authors state that while these data are reassuring

It should be noted that our findings are generalizable only to centers that are capable of providing obstetrical care similar to that outlined in the TBS, including but not limited to the presence of an experienced obstetrician at delivery and the ability to perform an urgent CD

Learn More – Primary Sources:

Delivery of monochorionic twins: lessons learned from the Twin Birth Study

Related ObG Topics:

Vaginal Delivery of Twin A and Cesarean Delivery for Twin B: Risk Factors and Outcomes

Twin Pregnancy Outcomes Following Confirmation of Viability in the First Trimester

Planned Cesarean or Planned Vaginal Delivery for Twins?

Is There a Role for Vaginal Delivery if First Twin is in Breech Presentation?