Single umbilical artery aneurysm: a rare case report and review of perinatal management.

BACKGROUND: Single umbilical artery aneurysms (SUAA) are extremely rare vascular malformations. Most of the times aneurisms are located in the cors insertion on the placenta, and are associated with increased perinatal morbidity, including fetal growth restriction and increased fetal mortality.

CASE PRESENTATION: This report describes a case of a single SUAA diagnosed by prenatal ultrasound at 22 weeks and 1 day of gestation. The characteristic ultrasound findings included cystic dilatation at the placental end of the umbilical cord, accompanied by disrupted blood flow on color Doppler imaging, indicative of abnormal umbilical artery expansion. At 37 weeks and 2 days of gestation, the presence of venous-like changes in the Doppler spectrum, accelerated peak systolic velocity (PSV) of the middle cerebral artery (MCA), and decreased pulsatility index (PI) raised concern for fetal intrauterine distress. An emergency cesarean section was performed. The neonate exhibited mild asphyxia at birth and was admitted to the neonatal intensive care unit (NICU). After 19 days of monitoring and treatment, the infant was discharged in stable condition.

CONCLUSION: SUAA is a rare but potentially fatal pregnancy complication, associated with increased fetal mortality and adverse perinatal outcomes. Early detection through ultrasound of cystic dilatation and disturbed blood flow patterns is crucial for optimizing perinatal management. Continuous monitoring of fetal growth, particularly the detection of fetal growth restriction (FGR) and abnormal fetal heart rate patterns, plays a vital role in reducing the risk of intrauterine distress and fetal demise. In cases of SUAA, elective cesarean delivery has been shown to effectively mitigate the risk of intrauterine hypoxia and fetal distress, thereby improving neonatal survival rates and long-term prognosis.