The twin-twin transfusion syndrome

Area of Science:

• Perinatology
• Maternal-Fetal Medicine
• Fetal Medicine

Background:

• Twin-twin transfusion syndrome (TTTS) is a severe complication of monochorionic-monoamniotic twin pregnancies.
• Current understanding of TTTS anatomy and pathogenesis has remained static for three decades.
• Advances in diagnostic imaging necessitate a re-evaluation of the syndrome's definition.

Purpose of the Study:

• To propose a new composite definition for twin-twin transfusion syndrome.
• To integrate modern diagnostic modalities into the definition of TTTS.
• To explore the impact of prenatal diagnosis on TTTS management.

Main Methods:

• Extensive literature review on TTTS anatomy and pathogenesis.
• Analysis of modern diagnostic tools: sonography and Doppler studies.
• Development of a new composite definition based on specific criteria.

Main Results:

• Proposed criteria for TTTS diagnosis include sonographic findings (abdominal circumference discordance >18mm, polyhydramnios-oligohydramnios, signs of monozygosity).
• Additional criteria involve Doppler velocimetry (inter-twin systolic/diastolic ratio difference >0.4), transplacental vascular shunt, birth weight difference (≥15%), and hemoglobin difference (≥5 g/dL).
• Prenatal diagnosis may enhance TTTS management, with intrauterine treatment of placental vascular anomalies showing potential efficacy.

Conclusions:

• A revised, composite definition of TTTS is proposed, incorporating advanced imaging and physiological parameters.
• Antenatal diagnosis through sonography and Doppler studies is crucial for identifying TTTS.
• Intrauterine interventions targeting placental vascular anomalies represent a promising therapeutic avenue for TTTS.