# TRAP Sequence Clinical Case: Is a Single Umbilical Artery a Protective Ultrasound Marker for Fetal Heart Failure Development

## TL;DR

A case study suggests that a single umbilical artery may protect the healthy twin from heart failure in a rare pregnancy complication called TRAP sequence.

## Contribution

The paper proposes a novel hypothesis that a single umbilical artery may act as a protective factor in TRAP sequence pregnancies.

## Key findings

- The pump twin showed normal growth and no signs of fetal heart failure despite the TRAP sequence.
- The presence of a single umbilical artery may reduce blood flow to the parasitic twin, potentially protecting the pump twin.
- Further research is needed to confirm the protective role of a single umbilical artery in TRAP pregnancies.

## Abstract

Twin Reversed Arterial Perfusion (TRAP) sequence is a rare complication in monochorionic pregnancies, often leading to fetal heart failure (FHF) in the pump twin. We present a 17-year-old primigravida with a monochorionic monoamniotic twin pregnancy presented with an acardiac twin, single umbilical artery (SUA), and multicystic placenta appearance. Throughout the pregnancy, the pump twin exhibited normal growth without signs of FHF. The infant was delivered at 34 weeks via cesarean section, healthy and without cardiac anomalies. The nonexistence of an impacted intrauterine fetal development and FHF of the pump twin in our case may be explained by the presence of one umbilical artery, resulting in less blood flow to the parasitic twin, which can be accepted as a protective factor for the pump twin circulation. Our hypothesis-generating finding that SUA may play a protective role in the development of FHF in pump-twin is promising; however, it remains speculative, and further research is needed to confirm the protective role of SUA for pump-twin outcomes in TRAP pregnancies.