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Professional Technical IVT

TRAP sequence

Also written as: TRAP — Twin Reversed Arterial Perfusion

Twin reversed arterial perfusion causing acardiac twin formation in monochorionic pregnancies.

Full Definition

TRAP (Twin Reversed Arterial Perfusion) sequence is a rare complication of monochorionic twin pregnancies where one twin (acardiac/recipient) receives deoxygenated blood from the other twin (pump/donor) through reversed flow in the umbilical artery. The acardiac twin typically lacks a functional heart and upper body structures, while the pump twin faces high-output cardiac failure due to perfusing both twins. This condition requires fetal intervention, typically cord occlusion or radiofrequency ablation, to prevent pump twin heart failure and improve survival rates.

Usage

Usage note: Always spell out the full term on first reference before using the acronym TRAP.

In Context

  • "TRAP sequence was diagnosed at 18 weeks with evidence of early pump twin cardiac compromise." — Maternal-fetal medicine consultation
  • "Radiofrequency ablation successfully interrupted the vascular connections in this case of TRAP sequence." — Fetal surgery operative report

Also known as

acardiac twinning twin reversed arterial perfusion

Don't confuse with

twin-to-twin transfusion syndrome conjoined twins
tocolysis ← Back to glossary twin-to-twin transfusion syndrome

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