ABSTRACT
Thrombosis of the umbilical cord vessels is a rare complication of pregnancy, combined with a high level of perinatal morbidity and mortality. Anomalies of vascular attachment (velamentous attachment), pathology of the umbilical cord (hyperspiralization, short or long umbilical cord), intrauterine infections, maternal diabetes mellitus and preeclampsia as well as meconium found in the amniotic fluid are among the risk factors of developing thrombosis in the umbilical cord vessels. Here we present two clinical observations of umbilical vein thrombosis at full-term pregnancy. In both cases, during pregnancy and childbirth, no signs of umbilical cord pathology were found according to cardiotocography and Doppler ultrasound;despite this, the children were born in hypoxic state. Both newborns were transferred to the second stage of treatment due to suspected intrauterine pneumonia. Velamentous attachment, intrauterine infections as well as meconium found in the amniotic fluid were the risk factors of developing umbilical vein thrombosis described in case 1 and case 2, respectively. During pregnancy, both female patients suffered from clinically confirmed novel coronavirus infection (COVID-19) and contacted patients with COVID-19 in the third trimester of gestation. It is likely that endothelial damage caused by the novel coronavirus SARS-CoV-2 was one of the risk factors for the development of umbilical vein thrombosis, but this issue requires to be further explored.