Spontaneous resolution of an umbilical cord arteriovenous fistula

Abstract

AbstractAn umbilical arteriovenous (AV) fistula is an extremely rare anomaly of the umbilical cord, with only one case being documented in the literature. The purpose of this report is to describe the prenatal sonographic characteristics of such a lesion and its potential complications. We report a case of an umbilical cord AV fistula detected at 24 weeks of gestation in one fetus of dichorionic-diamniotic twins. Color flow and spectral Doppler examinations showed a jet originating from one of the umbilical arteries entering the dilated umbilical vein. Serial ultrasounds revealed relative oligohydramnios and deep A waves in the ductus venosus for the affected twin. Upon performing fetal echocardiography assessment, mild cardiomegaly and dilatation of the inferior vena cava were detected. Chromosomal testing revealed a normal karyotype. The patient continued to be followed for close monitoring of fetal well-being and corticosteroids were administered. Cesarean section was planned for 28–30 weeks, but surprisingly, the oligohydramnios resolved, Doppler studies normalized, and no further intra-uterine growth restriction or fetal compromise was observed. Due to the recurrence of abnormal Doppler studies at 36 weeks of gestation, the patient was admitted for an induction of labor followed by a vaginal delivery of two healthy infants. Given the scarcity of reports regarding umbilical cord AV fistula, it is important to perform an extensive investigation of the affected fetus including karyotype and echocardiography. Furthermore, delivery timing should rely on close surveillance of fetal well-being to avoid the risk of fetal demise.