Perinatal complications of monochorionic placentation

Area of Science:

• Perinatology
• Fetal Medicine
• Reproductive Biology

Background:

• Twin-twin transfusion syndrome (TTTS) affects monochorionic diamniotic (MCDA) twins, characterized by unequal placental sharing.
• Discordant growth in MCDA twins is a significant concern, often associated with placental vascular anomalies.

Purpose of the Study:

• To review the pathophysiology of TTTS and growth restriction in MCDA twins.
• To update on recent findings regarding screening, mechanisms, and management of TTTS.

Main Methods:

• Review of current literature on TTTS pathophysiology and discordant growth in MCDA twins.
• Analysis of recent Doppler-based flow studies and genetic marker investigations.

Main Results:

• Discordant nuchal translucency (≥20%) can screen for TTTS and early loss.
• Size of arterio-venous anastomoses, not number or direction, dictates transfusion complications.
• High renin-angiotensin system (RAS) effectors in recipients suggest placental origin.
• Deep subchorionic vascular anastomoses have implications for laser treatment.
• Cerebral palsy rate is 5-17% among survivors.
• Transmitted umbilical artery Doppler patterns in MCDA twins increase risk of sudden death and cranial lesions in larger co-twins.

Conclusions:

• Further research is needed on the RAS role and deep vascular anastomoses in TTTS outcomes.
• Delivery at 32 weeks is recommended for MCDA twins with specific umbilical artery Doppler findings.