A partial supernumerary umbilical vein: a case report
Abnormalities in the number of vessels can be found for both the umbilical artery and vein. We sometimes encounter cases of a decreased number of umbilical cord vessels, such as a single umbilical artery. In contrast, there may be an increase from three to four vessels within the umbilical cord. A supernumerary umbilical vein is particularly very rare, and it is generally found in combination with congenital anomalies. We report a case of a partial supernumerary umbilical vein.
The previous pregnancy of a 37-year-old healthy Japanese woman (gravida 2, para 1) had been uncomplicated, and the resulting child was alive and well. Prenatal examination at 36 weeks of gestation revealed the coexistence of a four-vessel part and a normal three-vessel part of the umbilical cord. A healthy female neonate weighing 2726 g was born at 38 weeks of gestation. The umbilical cord measured 40 cm in length; the four-vessel part continued to a distance of 18 cm from the surface of the infant’s body, and the remaining umbilical cord comprised three vessels. On histological examination, the fetal side of the umbilical cord had two arteries and two veins, and the placental side had two arteries and one vein. Isolated supernumerary umbilical veins tend to be overlooked. We consider that it is important to evaluate the number of umbilical cord vessels in the second trimester using ultrasound combined with color Doppler in at least three sites: the insertion sites on both the fetal abdomen and placenta, and the free loop of the umbilical cord.
Prenatal diagnosis of isolated supernumerary umbilical cord vessels tends to be overlooked. However, supernumerary vessels of the umbilical can be associated with fetal congenital anomalies. The number of vessels within the umbilical cord must be examined because the detection of such abnormalities may lead to the prenatal diagnosis of other congenital anomalies.
KeywordsCase report Congenital anomaly Four-vessel umbilical cord Prenatal diagnosis Single umbilical artery Supernumerary umbilical vein
Persistent right umbilical vein
Single umbilical artery
Abnormalities in the number of vessels can be found for both the umbilical artery and vein. We sometimes encounter cases of a decreased number of umbilical cord vessels, such as a single umbilical artery (SUA). A SUA is associated with fetal growth restriction and cardiac and renal anomalies . In contrast, there may be an increase from three to four vessels within the umbilical cord. Meyer et al.  reported that it is more common to encounter an accessory fourth vessel of the umbilical cord than a SUA. Although a supernumerary umbilical vein is reportedly associated with a very high incidence of congenital anomalies , there are several reports of very rare isolated cases of a supernumerary umbilical cord (two arteries and two veins) without any fetal abnormality . We report a case of a partial four-vessel (two arteries and two veins) umbilical cord.
At 38 weeks of gestation, a healthy female neonate weighing 2726 g was delivered by spontaneous vaginal delivery. The infant’s Apgar scores were 9 and 10 at 1 minute and 5 minutes, respectively. The neonatal physical examination at birth was normal.
In the middle of the fourth week of gestation, the sinus venosus receives blood from the right and left sinus horns [6, 7]. Each sinus horn receives blood from three important veins: the vitelline or omphalomesenteric vein, the umbilical vein, and the common cardinal vein [6, 7]. During the fourth and fifth weeks of development, the sinus shifts to the right and the left sinus horn is rapidly lost [6, 7]. A complex pattern of vessel growth occurs, and the left vitelline and umbilical veins atrophy and disappear [6, 7]. Failure of this process results in a persistent right umbilical vein (PRUV) .
A PRUV usually replaces the normal left umbilical vein or is supernumerary . Schimmel and Eidelman  and Avnet et al.  reported that a supernumerary umbilical vein results in a four-vessel umbilical cord. In contrast, Canavan and Hill  reported that 24 of 313 infants with PRUV had a four-vessel umbilical cord. Murdoch  reported an anomalous cord containing two umbilical veins and a segment of double cord. In the present case, we found a normal left umbilical vein with a four-vessel umbilical cord. Several variations of supernumerary umbilical veins have been described; however, the pathogenesis of such variations remains unknown.
The present case of an isolated four-vessel umbilical cord was diagnosed in the third trimester. Lei et al.  reported that the presence of a four-vessel umbilical cord was diagnosed prenatally as the sole issue in seven of 16 cases; in the remaining nine cases, a four-vessel umbilical cord was diagnosed in combination with fetal growth restriction, oligohydramnios, and a variety of anomalies such as bilateral cleft lip and palate, esophageal atresia, atrioventricular septal defect, PRUV, hypertrophic cardiomyopathy, anterior chest wall defect, and heterotaxy syndrome. It is considered difficult to diagnose an abnormal number of umbilical vessels prenatally, even if other congenital abnormalities coexist. While a SUA can be easily detected by the presence of only one umbilical artery lateral to the fetal bladder, the presence of supernumerary umbilical veins tends to be overlooked, as it is often difficult to check the number of umbilical veins throughout the length of the umbilical cord. We consider that it is important to evaluate the number of umbilical cord vessels in the second trimester using ultrasound combined with color Doppler in at least three sites: the insertion sites on both the fetal abdomen and placenta, and at more than one point in the free loop of the umbilical cord.
Prenatal diagnosis of isolated supernumerary umbilical cord vessels tends to be overlooked. However, supernumerary vessels of the umbilical can be associated with fetal congenital anomalies. The number of umbilical cord vessels must be examined because abnormalities may suggest the presence of congenital anomalies.
We thank Dr Goichi Furuno of the Furuno St. Maria Clinic for supporting this report. We also thank Kelly Zammit, BVSc, from Edanz Group (www.edanzediting.com/ac), for editing a draft of this manuscript.
The authors declare that they have no funding source.
Availability of data and materials
All data used in this study are available from the corresponding author on request.
Both MKs and MM analyzed the case and wrote the manuscript. TM and EO performed neonatal physical and ultrasound examinations. YT and MH performed the histological examination of the umbilical cord. All authors critically reviewed and revised the manuscript. All authors read and approved the final manuscript.
Ethics approval and consent to participate
Ethics committee approval was not applicable, because this is a case report of one patient.
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Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
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