Umbilical artery aneurysm without aneuploidy and delivery of a live neonate

Umbilical artery aneurysm, a rare structural anomaly of the umbilical cord, is frequently associated with fetal aneuploidy, fetal growth restriction and fetal demise. At present there are no definitive protocols or guidelines for the surveillance and management of this condition.

The index case is an 18-year-old primigravida who had an ultrasound at 35 weeks and 5 days gestation due to lagging symphysio-fundal height measurement. The ultrasound scan revealed a normal fetus with estimated fetal weight that was appropriate for gestational age. There was a cystic structure with internal echoes originating from the placenta at the point of the umbilical cord insertion, which was determined to be a 1.9 × 1.8 cm umbilical artery aneurysm on 3D and Doppler imaging. On follow up imaging the aneurysm had increased in size and measured 3.06 × 1.79 cm. The patient subsequently had a cesarean section delivery of a live female. Karyotyping subsequently revealed 46 XX.

A total of 15 cases of umbilical artery aneurysm have been reported in the literature to date, of which there were 5 live born infants with normal karyotype. The remaining 10 cases were intra-uterine fetal demise or trisomy 18 with subsequent neonatal deaths. When monitoring the aneurysms with ultrasound, change in size and Doppler indices play a pivotal role in helping to determine time and mode of delivery and thus allow for a favorable perinatal outcome.