Do umbilical cord wrapped around the fetal body can mimic signs of aortal coarctation?

Objectives
Coarctation of the aorta (CoA) is an irreversible congenital heart defect. Its prenatal diagnosis is not rare a subject to false-positive conclusion. We present a novel hypothesis explaining the basis of this error.

Methods
Ten cases of prenatal suspicion of the coarctation of the aorta (based on disproportion at the level of 4 chamber view and mediastinum) coincidenced with the umbilical cord wrapped around the fetal body were found in the Filemaker datebase of the Fetal Cardiology Department. Only single pregnancies were taken into account. In all cases another cardiac and extracardiac malformations were excluded.

Results
The mean maternal age was 29,6 years. The mean gestational age was 33 7/8 weeks. All fetuses were in a good cardiovascular condition. The usual position of the umbilical cord was neck, but they were also location such as nucha, abdomen or lower limb. At birth, all newborns had normal anatomy of the heart. We conclude that the explanation of the false diagnosis was haemodynamic, resulting from the compression of the fetal neck by the umbilical cord that resulted in a disproportion of cardiac blood flow, “mimicking” CoA.

Conclusions
1. Functional disturbances can mimic prenatal CoA. 2. Umbilical cord position (specially enlacing the fetus neck) should be taken into consideration in suspected cases of fetal CoA.