A case of foetal intra-abdominal umbilical vein varix with adjacent extra-abdominal vein constriction

The Development of the Umbilical Vein and Its Anatomical and Clinical Significance

The umbilical vein is one of the most essential vessels in the human embryo. Anatomical structures though may vary in several cases. During the fourth and eighth weeks of gestation, the umbilical cord is formed. Initially, two umbilical arteries and veins exist. During development, the obliteration of the right umbilical vein occurs. The fetus and its liver receive macronutrients and oxygen from the placenta via the umbilical vein, which primarily supplies the left lobe of the liver before branching into the left portal vein and the ductus venosus. The ductus venosus directs blood from the umbilical vein directly into the systemic circulation through the inferior vena cava and right atrium, bypassing the fetal liver. In some cases, variations are observed. Disorders of the umbilical veins may involve the persistence of embryological structures, abnormal insertion or course, and the presence of supernumerary vessels. For example, the persistence of the right umbilical vein, duplication of the umbilical vein, and umbilical vein varix are some important variations to acknowledge in order to be able to understand the potential outcomes of the newborn. The majority of venous system anomalies are rare, and some may remain completely asymptomatic. Different forms of umbilical cord abnormalities, however, may be potentially fatal or pose a serious threat to fetal health. Therefore, clinically, early detection of these malformations is highly important in order to make a proper diagnosis and management of care. The aim of this study is to acknowledge the different types of umbilical vein variations through its development and its relation with liver parenchyma in order to achieve a better understanding and planning in surgical interventions. An advanced review search of the literature was undertaken. The literature review was conducted using the search engine of the PubMed database and Google Scholar. The years included in data collection were 1960-2022. All articles that met the inclusion criteria were taken under consideration.

Isolated fetal umbilical vein varix and the association with intrauterine fetal death and fetal growth restriction: A systematic review, meta-analysis, and nested retrospective cohort study

OBJECTIVES

To assess the risk of intrauterine fetal death (IUFD) and fetal growth restriction (FGR) in fetuses with an isolated fetal intra-abdominal umbilical vein varix (i-FIUVV).

METHODS

A retrospective cohort study combined with a systematic review and meta-analysis of the literature was performed. In the retrospective cohort study, all singleton fetuses with an i-FIUVV in the fetal medicine units of the Amsterdam UMC (between 2007 and 2023) were analyzed. The primary outcome measures were IUFD and FGR. The sample proportions of IUFD and FGR were depicted as risk percentages. The IUFD proportion was compared to the regional reference population and the FGR proportion was compared to the reported proportions in Europe. The secondary outcome measures were gestational age at diagnosis, initial and maximal FIUVV diameter, fetal monitoring in pregnancy, turbulent flow in the varix, thrombus formation in the varix, induction of labor, gestational age at birth, and birthweight centile. The proportion of fetuses with a birthweight below the 10th centile was compared with that of the regional reference population. The systematic review included all cases from eligible literature published between 2007 and 2023 supplemented by the data of our retrospective cohort study. In the systematic review and meta-analysis, the pooled proportions of IUFD and FGR were assessed in fetuses with i-FIUVV.

RESULTS

The retrospective cohort included 43 singletons with an i-FIUVV. The IUFD risk was 0% [Confidence Interval, CI: 0%-8.2%], which did not differ significantly from 0.3% in the reference population, p = 1.0. The risk of FGR was 16.3% [CI: 6.8%-30.7%] in the studied population, which is higher than the reported incidence of FGR in Europe ranging from 5%-10%. The proportion of fetuses with birthweights below the 10th centile was higher in our cohort compared with the reference population (23.3 vs. 9.9%, p < 0.01). The systematic review included 12 articles, three abstracts, and our current cohort. In total, 513 cases with an i-FIUVV were included. The pooled risk was 0.4% [CI: 0.1%-1.7%] for IUFD and 5.2% [CI: 1.1%-21.3%] for FGR. The mean gestational age at birth did not exceed 39 weeks in neither the cohort (38.7 weeks) nor the pooled literature (37.6 weeks).

CONCLUSION

An i-FIUVV in singletons is not associated with an increased IUFD risk up to 39 weeks of gestation but is possibly associated with FGR. The incidence of FGR in our cohort was higher than in the pooled literature (16.3% vs. 5%) but FGR definitions in the included studies varied. The proportion of birthweights below the 10th percentile in our cohort was significantly higher than in the reference group. Thus, based on these findings, we suggest conducting sonographic growth assessments while simultaneously assessing the i-FIUVV. No further monitoring and follow-up are indicated up to 39 weeks of gestation. After 39 weeks of gestation, data on fetuses with i-FIUVV and their outcomes are lacking.

A new classification of congenital abnormalities of UPVS: sonographic appearances, screening strategy and clinical significance

The umbilical–portal venous system (UPVS) plays an important role in embryonic development, as well as a significant blood circulation system to ensure the normal blood supply of fetal heart and brain and other vital organs. Congenital anomalies of UPVS contain many subtypes with a broad spectrum of manifestations and prognoses. Furthermore, because of fetal small lumen of UPVS, the sonographic evaluation remains difficult in utero. Appreciation of normal embryology and anatomy of UPVS is essential to an understanding of sonographic characteristics of anomalies of UPVS and fetal sequential changes. Through reviewing previous references and our experience with congenital abnormalities of UPVS, a new comprehensive classification is proposed. The new classification identifies three types of congenital abnormalities of UPVS based on morphological abnormalities and shunts. The embryology and etiology, sonographic, clinical and prognostic characteristics of each subtype of the new classification are described in detail. Knowledge of congenital abnormalities of UPVS can give sonographers a clue and aid prenatal sonographic diagnosis. The purpose of this article is to help the sonographers to understand the new classification of congenital abnormalities of UPVS, master the sonographic characteristics of each subtype and prenatal ultrasonographic screening strategy, and guide subsequent appropriate counseling and management.

Severe Consumptive Coagulopathy in an Extremely-Low-Birth-Weight Infant with Intra-Abdominal Umbilical Vein Varix: A Case Report

Recent studies have shown favorable outcomes for intra-abdominal umbilical vein varices (IUVVs) in term neonates who have no other complications. Little is known, however, about the prognosis of IUVVs in preterm neonates. We encountered a case of IUVV in an extremely low-birth-weight infant who developed severe consumptive coagulopathy after birth. The patient's coagulation test normalized as the varix spontaneously obstructed. Although life-threatening hemorrhagic complications were avoided, a cerebellum hemorrhage was found in the brain magnetic resonance imaging at the term-equivalent age. In a literature survey, coagulopathy was reported in 4 out of 15 infants with IUVVs born before 34 weeks of gestation, including our present case. Preterm infants with IUVVs may develop coagulopathy because of the prematurity of their coagulation-fibrinolysis systems. Attention should be given to the coagulation status of preterm neonates with IUVVs.