Background The objective of the study was to present the rupture of velamentous vessels as a rare but dangerous complication of pregnancy associated with high neonatal risk. Diagnosis of velamentous insertion of umbilical vessels is important to recognize because of the possibility of their rupture during labor. If the condition remains unrecognized, the most important step during labor is prompt and timely treatment of the multidisciplinary team in order to reduce fetal and neonatal mortality and morbidity. Case presentation We present two cases of ruptured velamentous vessels, both with good outcomes: in the first case the baby was delivered vaginally after a spontaneous rupture of the velamentous vessels, and in the second case an emergency cesarean section was performed. Conclusions Although bleeding caused by the rupture of velamentous vessels is not frequent, the consequences can be serious. The proper diagnosis of the umbilical cord insertion is mandatory during the mid-trimester anomaly scan, but in most cases the condition remains unrecognized until delivery. In the case of a rupture, a prompt reaction of the medical team is crucial in order to save the baby. Sometimes only an urgent 0 Rh negative blood transfusion can avoid a poor neonatal outcome.