We describe two cases of umbilical cord (UC) angiomyxoma diagnosed prenatally by sonography in the second trimester of pregnancy. In both cases, a complex mass was detected at the placental insertion site, characterized by an echoic nodule surrounding the umbilical vessels and distal edematous Wharton's jelly. Follow-up scans showed that the mass grew mainly at the expense of its edematous component, with normal uteroplacental Dopplers throughout the remaining of the pregnancy. However, late-onset fetal growth restriction complicated the progress of pregnancy, requiring delivery by Cesarean section at 37 weeks' gestation in both cases. Neonatal courses were unremarkable. An extensive review of the English literature was also performed, collecting 45 similar cases including ours. Our experience as well as the review of the literature confirms that UC angiomyxoma is an uncommon, sporadic condition that is usually detected incidentally during prenatal sonography and presents as an isolated finding. Nevertheless, it represents a high-risk condition for pregnancy complications including prematurity, fetal growth restriction, and fetal demise.