A case of a pregnant woman giving birth to a healthy neonate, complicated with a hypercoiled umbilical cord and umbilical artery thrombosis(和訳中)

The umbilical vessels have two arteries and one vein, and thrombosis rarely occurs in the umbilical vein and arteries. Umbilical artery thrombosis (UAT) has a low incidence rate compared with umbilical venous thrombosis. Discordant umbilical arteries (DUAs), wherein the size of the arteries is different, has rarely been reported, and the smaller umbilical artery has also been described as the hypoplastic umbilical artery (HUA). UAT and HUA/DUAs can be related to poor perinatal outcomes or fetus malformation. We herein present a case of a nulliparous and primigravid 37-year-old Japanese pregnant woman, with sonographic diagnosis of single umbilical artery at 24 weeks of gestation by the loss of left-sided umbilical artery. Subsequently, serological test showed elevated serum immunoglobulin M (IgM) and IgG antibodies for cytomegalovirus (CMV). Neither morphological nor growth abnormality of the fetus was sonographically found, and no CMV DNA was detected in the vaginal discharge. Clinical follow-up was performed, and the fetus was small for gestational age during the course of the observation. At 40 and 5/7 weeks of gestation, vaginal delivery was attempted, but cesarean delivery was performed because fetal distress was suspected by cardiotocography. An appropriate-for-age female neonate without anomaly was born, and the Apgar score was 8 and 9 after 1 and 5 min, respectively. Neither elevated serum anti-CMV IgM antibodies nor presence of CMV DNA in the urine was found in the neonate. Six days after cesarean section, the mother and neonate were discharged without any problems. A thin and hypercoiled umbilical cord was found macroscopically, and pathology confirmed that the umbilical cord had one vein and two arteries, which included an HUA showing occlusive thrombosis. The placenta showed no apparent abnormalities except for a small infarction at the marginal zone. CMV infection was not found in the umbilical cord and placenta. The pathogenesis of UAT was speculated to be related to the hypercoiled umbilical cord. This is the first case of a healthy, appropriate-for-age, full-term neonate born with UAT.