BACKGROUND AND PURPOSE:

• Litwinska et al. (Ultrasound in Obstetrics & Gynecology, 2019) compared pregnancy outcomes in twin pregnancies with two live fetuses at 11 to 13 weeks
• Laser surgery for severe TTTS and sFGR was also incorporated to assess the outcome of MCDA twins

METHODS:

• Retrospective analysis of prospectively collected data (between 2002 and 2019)
• Participants
  • Twin pregnancies undergoing routine ultrasound examination at 11 to 13 weeks
  • No anomalies
• Study design
  • Compared dichorionic (DC), monochorionic diamniotic (MCDA) and monochorionic monoamniotic (MCMA) for the following outcomes
    • Overall survival | Fetal loss at < 24 weeks’ gestation | Perinatal death at ≥ 24 weeks | Delivery at < 37 and < 32 weeks | Birth weight < 5th percentile

RESULTS:

• A total of 6,225 twin pregnancies were examined
  • DC: 78.7%
  • MCDA: 20.5%
  • MCMA: 0.9%
• Loss at < 24 weeks’ gestation
  • DC twins: 2.3%
  • MCDA twins: 7.7%
    • Relative risk (RR) 3.258 (95% CI, 2.706 to 3.923)
  • MCMA twins: 21.8%
    • RR 9.289 (95% CI, 6.377 to 13.530)
• Perinatal death at ≥ 24 weeks in all twins that were alive at 24 weeks
  • DC twins: 1.0%
  • MCDA twins: 2.5%
    • RR 2.456 (95% CI, 1.779 to 3.389)
  • MCMA twins: 9.3%
    • RR 9.130 (95% CI, 4.584 to 18.184)
• Preterm birth at < 37 weeks’ gestation in pregnancies with at least one liveborn twin
  • DC twins: 48.6%
  • MCDA twins: 88.5%
    • RR 1.824 (95% CI, 1.760 to 1.890)
  • MCMA twins: 100%
    • RR 2.060 (95% CI, 2.000 to 2.121)
• Preterm birth at < 32 weeks
  • DC twins: 7.4%
  • MCDA twins: 14.2%
    • RR 1.920 (95% CI, 1.616 to 2.281)
  • MCMA twins: 26.8%
    • RR 3.637 (95% CI, 2.172 to 6.089)
• SGA (with at least one liveborn twin)
  • DC twins: 31.2%
  • MCDA twins: 37.8%
    • RR 1.209 (95% CI, 1.138 to 1.284)
  • MCMA twins: (33.3%)
    • Not statistically different from DC
• 10% of MCDA twins had endoscopic laser ablation for twin–twin transfusion syndrome (TTTS) and/or selective fetal growth restriction (sFGR)
  • Both fetuses survived: 55.9% of cases
  • One fetus survived: 22.5%
  • No survivors: 21.6%  
  • Total fetal loss rate at < 24 weeks’ gestation for MCDA twins would have been 13.5% if laser intervention had not been performed  

CONCLUSION:

• Compared to DC twins, fetal loss, perinatal death, and preterm birth are elevated for MCDA and especially MCMA twins
• Fetal loss rate for MCDA twins mitigated by the use of laser surgery been used for all cases of early TTTS and/or sFGR
• The authors suggest how the data from this study be used

These data would be useful in counseling parents as to the likely outcome of their pregnancy and in defining strategies for surveillance and interventions in the management of the different types of twin pregnancy 

Learn More – Primary Sources:

Outcome of twin pregnancy with two live fetuses at 11–13 weeks’ gestation

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