Sonographic findings of the umbilical cord: implications for the risk of fetal chromosomal anomalies

Placental and Umbilical Cord Anomalies Diagnosed by Two- and Three-Dimensional Ultrasound

The aim of this review is to present a wide spectrum of placental and umbilical cord pathologies affecting the pregnancy. Placental and umbilical cord anomalies are highly associated with high-risk pregnancies and may jeopardize fetal well-being in utero as well as causing a predisposition towards poor perinatal outcome with increased fetal and neonatal mortality and morbidity. The permanent, computerized perinatology databases of different international centers have been searched and investigated to fulfil the aim of this manuscript. An extended gallery of prenatal imaging with autopsy correlation in specific cases will help to provide readers with a useful iconographic tool and will assist with the understanding and definition of this critical obstetrical and perinatological issue.

Stereological and Histological Assessment of the Umbilical Cord in New-Born Rat

BACKGROUND

Umbilical cord plays a crucial role in the continuation of pregnancy by transferring nutrition and oxygen across the placenta to the fetus. We aimed to investigate the morphometrical and histological features of the umbilical cords in new-born rats.

MATERIALS AND METHODS

The adult male and female rats were chosen for matting purpose in the present study. Briefly, ten adult Wistar albino rats (female, n = 5; male, n = 5) were randomly assigned into five groups of two animals (female, n = 1; male, n = 1). Immediately after parturition, two umbilical cords of new-born rats (0-day-old) from each group were randomly selected. Finally, ten umbilical cord samples were examined using the histological and stereological methods in the light and electron microscopes.

RESULTS

The total numbers of Hofbauer cells and mesenchymal stromal cells was estimated statistically. We also calculated the mean volume of umbilical cords, arteries and veins, as well as arterial and venous lumens. Our histological findings also exhibited the histological features of Hofbauer cells, mesenchymal stromal cell cells, and blood vessels.

CONCLUSION

Our findings showed more detailed information about umbilical cord tissues and their components, and that may contribute to the diagnose of umbilical cord complications in the developing fetus.

Prenatal Diagnosis of Umbilical Cord Ulcer: A Report of Two Cases

Umbilical cord ulcer is related to fetal intestinal atresia or meconium; perforation of the ulcer causes fetal deterioration leading to fetal and neonatal death owing to fetal hemorrhage. However, to the best of our knowledge, a method to diagnose umbilical cord ulcer prenatally is not available. No reports exist about the prenatal findings before perforation of umbilical cord ulcer using ultrasonography. We encountered two cases of umbilical cord ulcer showing ultrasonographic finding of a linear echo around the umbilical cord. Umbilical cord ulcers with an exposed umbilical cord artery in the first case and with perforation of the artery in the second case were diagnosed postnatally. When we encounter such ultrasonographic finding, especially with polyhydramnios and high amniotic bile acid concentration in cases of fetal intestinal atresia, risk of perforation of the umbilical cord ulcer should be included in the differential diagnosis.

Isolated Single Umbilical Artery and Fetal Echocardiography: A 25-Year Experience at a Tertiary Care City Hospital

OBJECTIVES

To review our 25-year experience with a single umbilical artery and fetal echocardiography to estimate the need for this test in cases of an isolated single umbilical artery.

METHODS

We conducted a retrospective review of 436 patients with a diagnosis of a single umbilical artery at our institution between 1990 and 2015. Two hundred eighty-eight women had both an anatomic survey and a fetal echocardiogram. Pregnancies with concurrent extracardiac anomalies or aneuploidy were excluded. The study population was divided into 3 groups based on cardiac views on the anatomic survey: normal, incomplete, and suspicious. Echocardiographic results were compared among the 3 groups. The primary outcome measure was the incidence of cardiac anomalies in the normal group at fetal echocardiography. The data were analyzed by the χ² test or Fisher exact test.

RESULTS

The mean maternal age ± SD of the group was 29.2 ± 6.2 years; 44.1% were primiparas. The mean gestational age at diagnosis was 22.6 ± 5.2 weeks, and the mean gestational age at fetal echocardiography was 25.1 ± 3.6 weeks. In the normal group, 99.1% (230 of 232) of women had a normal fetal echocardiogram; the 2 abnormal cases were ventricular septal defects. Normal echocardiograms were obtained in 81.8% (36 of 44) and 25.0% (3 of 12) of the "incomplete" and "suspicious" groups, respectively.

CONCLUSIONS

Fetuses with a single umbilical artery, in the absence of structural abnormalities, and with normal cardiac views at the time of the anatomic survey do not warrant an echocardiogram.

Sonographic Estimation of Umbilical Cord Cross-section Area and its Reference Value in Normal Pregnancy

INTRODUCTION

The routine antenatal sonographic investigations of the umbilical cord are limited for assessment of number of umbilical vessels and doppler evaluation of umbilical blood flow. With the advancements of the sonographic techniques it is now possible to have more detailed evaluation of umbilical cord. There exist only few literatures on assessment of umbilical cord cross-sectional area during pregnancy to provide a baseline reference value.

AIM

To establish the reference intervals of cross-sectional area of the umbilical cord during gestation and to find the correlation of umbilical cord cross-sectional area with the foetal anthropometric measurements.

MATERIALS AND METHODS

This study was conducted among 214 normal pregnant women who underwent a routine antenatal sonogram during gestational age ranging from 24-39 weeks in the Department of Radiodiagnosis. The umbilical cord cross-sectional area was calculated at a plane immediately close to the umbilical cord insertion to the foetal abdomen. The following foetal parameters were studied: Biparietal Diameters (BPD), Head Circumference (HC), Abdominal Circumference (AC), Femur Length (FL), and Estimated Foetal weight (EFW). The relationship between foetal anthropometric measurements and umbilical cord cross sectional area was assessed using spearman rank correlation. The 5^th, 10^th, 50^th, 90^th and 95^th percentiles of umbilical cord cross-sectional area were calculated for each gestational groups using polynomial regression analysis.

RESULTS

A statistically significant correlation was observed between cross-sectional area of umbilical cord with both gestational age and foetal anthropometric parameters. The mean age of study population was 25.08±3.5 years and the mean gestational age was 34.42±2.5 weeks. We observed a strong correlation between head circumference and umbilical cord cross-sectional area.

CONCLUSION

The mean umbilical cord cross-section area increases steadily with gestational age for up to 34 weeks and then it declines. Umbilical cord cross-sectional area can be easily measured and hence it can be included in routine antenatal sonographic evaluations to predict the perinatal outcome. Careful monitoring of the pregnancy is needed in case of abnormal cross-sectional area measurements.

Longitudinal reference range for umbilical cord cross-sectional area in twin pregnancies at 18-32 weeks of gestation

OBJECTIVES

The objectives of this study were to establish gestational age-specific reference ranges for cross-sectional area of the umbilical cord, and its components, in twin pregnancies and to compare them with previously reported singleton reference ranges.

METHODS

This was a prospective longitudinal study involving uncomplicated dichorionic twin pregnancies. Sonographic measurements of the cross-sectional area of the umbilical cord, umbilical vein and arteries and Wharton's jelly were obtained in a plane adjacent to the fetal abdomen, every 3 weeks, between 18 and 32 weeks of gestations. Multilevel regression analysis was used to determine gestational age-specific reference ranges for each parameter, and these were plotted against singleton pregnancy references.

RESULTS

Three hundred and thirty four ultrasound scans were performed in 44 twin pregnancies, between 18 and 32.9 weeks (mean: 3.8 ± 0.7 scans/pregnancy and mean interval between scans: 3.3 ± 0.9 weeks). All umbilical cord cross-sectional areas (total, vein, artery and Wharton's jelly) showed a significant increase with gestational age. Compared with singleton pregnancy ranges, mean values were considerably lower in twin pregnancies and resemble the lower limits observed in singletons.

CONCLUSION

In twin pregnancies, cross-sectional area of the umbilical cord, and its components, increases between 18 and 32 weeks, and mean values are substantially lower compared with singleton pregnancies.

Comprehensive imaging review of abnormalities of the umbilical cord

A complete fetal ultrasonographic (US) study includes assessment of the umbilical cord for possible abnormalities. Knowledge of the normal appearance of the umbilical cord is necessary for the radiologist to correctly diagnose pathologic conditions. Umbilical cord abnormalities can be related to cord coiling, length, and thickness; the placental insertion site; in utero distortion; vascular abnormalities; and primary tumors or masses. These conditions may be associated with other fetal anomalies and aneuploidies, and their discovery should prompt a thorough fetal US examination. Further workup and planning for a safe fetal delivery may include fetal echocardiography and karyotype analysis. Doppler US is a critical tool for assessment and diagnosis of vascular cord abnormalities. US also can be used for follow-up serial imaging evaluation of conditions that could result in fetal demise. Recent studies suggest that three- or four-dimensional Doppler US of the fetal umbilical cord and abdominal vasculature allows more accurate diagnosis of vascular abnormalities. Doppler US also is invaluable in assessment of fetal growth restriction since hemodynamic changes in the placenta or fetus would appear as a spectral pattern of increased resistance to forward flow in the fetal umbilical artery. Early detection of umbilical cord abnormalities and close follow-up can reduce the risk of morbidity and mortality and assist in decision making.

Relationship between sonographic umbilical cord size and gestational age among pregnant women in Enugu, Nigeria

BACKGROUND

Common fetal parameters for gestational age (GA) estimation have pitfalls especially in advanced pregnancy and pregnancy complicated by fetal structural anomaly.

OBJECTIVE

To assess the relationship between umbilical cord size and gestational age of the fetus.

SUBJECTS AND METHODS

A sonographic cross sectional study involving 300 pregnant women with GA between 14 weeks to 40 weeks was done in Enugu, Nigeria. Gestational ages were first estimated by use of Naegele's formula for GA estimation based on the date of onset of each subject's last menstrual period. Fetal parameters such as biparietal diameter, femur length, head circumference and abdominal circumference were measured and also used to estimate GA. Umbilical cord diameters were measured and used to compute the umbilical cord cross-sectional area.

RESULTS

The mean umbilical cord diameter and cross-sectional area were 14.5mm ± 7.2mm and 201.6mm ± 139.5mm(2) respectively. Umbilical cord growth rate of 1.0mm/week was noted between the 14(th) and 35(th) week of pregnancy. There were significant correlations (p < 0.001) between umbilical cord size and other fetal parameters for GA estimation.

CONCLUSION

Umbilical cord size had strong linear relationship with common fetal GA estimation parameters and could be used to compliment these parameters for GA estimation.

Sonographic measurement of the umbilical cord area and the diameters of its vessels during pregnancy

The objective was to determine the cross-sectional area of the umbilical cord, its diameter and the diameter of its vessels to establish a reference curve for these parameters during pregnancy, through a prospective cross-sectional study, including 2,310 low-risk pregnancies between 12 and 40 weeks' gestation. Means and standard deviations (SDs), plus the 10th, 50th and 90th percentiles for each measurement were calculated using polynomial regression analysis. Mann-Whitney, Kruskal-Wallis and Wilcoxon tests were used for statistical analysis. These parameters increased significantly with gestational age. The area of the cord also varied significantly with parity. Their new reference curves for low risk pregnancies were calculated using polynomial regression, and an almost linear increase in values was found up to 32 weeks of pregnancy, tending to stabilise from then onwards. The regression equation of the umbilical cord area according to gestational age (GA) was: -1.417 + 0.3026*GA-0.008*GA(2) + 0.000007*GA(3) and the degree of adjustment (R(2)) was 0.89.

Comparative proteomic analysis of malformed umbilical cords from somatic cell nuclear transfer-derived piglets: implications for early postnatal death

Background

Somatic cell nuclear transfer (scNT)-derived piglets have high rates of mortality, including stillbirth and postnatal death. Here, we examined severe malformed umbilical cords (MUC), as well as other organs, from nine scNT-derived term piglets.

Results

Microscopic analysis revealed complete occlusive thrombi and the absence of columnar epithelial layers in MUC (scNT-MUC) derived from scNT piglets. scNT-MUC had significantly lower expression levels of platelet endothelial cell adhesion molecule-1 (PECAM-1) and angiogenesis-related genes than umbilical cords of normal scNT piglets (scNT-N) that survived into adulthood. Endothelial cells derived from scNT-MUC migrated and formed tubules more slowly than endothelial cells from control umbilical cords or scNT-N. Proteomic analysis of scNT-MUC revealed significant down-regulation of proteins involved in the prevention of oxidative stress and the regulation of glycolysis and cell motility, while molecules involved in apoptosis were significantly up-regulated. Histomorphometric analysis revealed severe calcification in the kidneys and placenta, peliosis in the liver sinusoidal space, abnormal stromal cell proliferation in the lungs, and tubular degeneration in the kidneys in scNT piglets with MUC. Increased levels of apoptosis were also detected in organs derived from all scNT piglets with MUC.

Conclusion

These results suggest that MUC contribute to fetal malformations, preterm birth and low birth weight due to underlying molecular defects that result in hypoplastic umbilical arteries and/or placental insufficiency. The results of the current study demonstrate the effects of MUC on fetal growth and organ development in scNT-derived pigs, and provide important insight into the molecular mechanisms underlying angiogenesis during umbilical cord development.

Inter- and intra-observer variability in Sonographic measurements of the cross-sectional diameters and area of the umbilical cord and its vessels during pregnancy

BACKGROUND

The purpose of the study was to evaluate inter- and intra-observer variability in sonographic measurements of the cross-sectional area of the umbilical cord and the diameters of its vessels in low-risk pregnancies of 12 to 40 weeks of gestation.

METHODS

A prospective cross sectional study was performed in 221 pregnant women at different gestational ages. Measurements were carried out also by a second observer to evaluate inter-observer variability and repeated once again by the first observer to assess intra-observer variability. The linear correlation between the measurements (Spearman's coefficient of correlation) and their reliability through the intraclass correlation coefficient (ICC), the Cronbach's alpha coefficient and the limits of agreement proposed by Bland and Altman were evaluated.

RESULTS

The results showed that inter-observer and intra-observer variability did not show any significant difference between examiners. A good linear correlation between the measurements and reliability was obtained, with values of R, ICC and Cronbach's alpha all above the standard limits.

CONCLUSION

It is possible to conclude that inter- and intra-observer variability in the measurements of the umbilical cord and its vessels was small; their reliability and agreement were good.

Nurses' guide to early detection of umbilical arterial catheter complications in infants

Umbilical arterial catheters (UAC) are routinely used in the care of critically ill newborns. Complications related to UACs include vascular compromise, hemorrhage, complications related to malposition, severance of the catheter itself, and infection. This article is Part II in a series dedicated to assessing infants with an umbilical catheter. Part I focused on infants with umbilical venous catheters; this article will focus on the physical assessment relevant to infants with an UAC. Complications related to UACs can occur during any phase of treatment: insertion, while indwelling, or after discontinuing the catheter. Review of clinical signs of complications along with clinical photographs, will assist caregivers in promptly recognizing UAC-related complications.

Rare case of exomphalos complicated with umbilical cord teratoma in a fetus with trisomy 13

An exomphalos containing unusual solid and cystic mass was diagnosed during a routine ultrasound examination in the 17th week of gestation. Further investigations were planned but the pregnancy was terminated. The fetopathological examination revealed an umbilical cord teratoma. Although this entity is very rare it should be emphasized as a possible differential diagnosis when cystic lesion of the cord is detected. Large teratomas associated with abdominal wall defect may have poor fetal outcome and can be associated with structural and chromosomal abnormalities. In our case trisomy 13 was diagnosed.

Foetal cystic abdominal masses

Foetal abdominal cysts are frequently found on routine antenatal ultrasound. Various sonographic features might help in their differential diagnosis. However, a definitive diagnosis is often not made until postnatal life, and detection of an intra-abdominal cyst antenatally rarely alters obstetric management. A review of possible causes of a foetal abdominal cyst is presented.

Umbilical cord pseudocyst in a fetus with trisomy 18

An umbilical cord pseudocyst was detected in the 28th week of gestation in a fetus complicated with growth restriction and polyhydramnios. The combination of cord pseudocysts, growth restriction, and polyhydramnios prompted us to perform a detailed ultrasonographic examination (gray scale and three-dimensional), which revealed the presence of micrognathia, overlapping fingers, and congenital heart defects, features characteristic of trisomy 18. Karyotyping confirmed a diagnosis of trisomy 18. After spontaneous labor onset, the infant was delivered at 31 weeks of gestation, and died soon after delivery. An umbilical cord pseudocyst is a good marker for the prenatal detection of trisomy 18.

Look before you clamp: delivery room examination of the umbilical cord

The umbilical cord is a critical connection between the embryo (and later, the fetus) and the placenta. The umbilical cord houses the blood vessels that are responsible for nourishing the fetus. Proper umbilical cord function is essential for growth and development before birth. A review of the embryologic origin of the umbilical cord aids in understanding abdominal wall and umbilical cord defects that can present in the newborn period. In the delivery room, inspection of the umbilical cord is an integral part of the first minutes of life. Any abnormality either within the cord structure or in the areas surrounding the base of the cord may necessitate a delay in shortening the cord. Surgical consultation may also be indicated. This issue of Focus on the Physical will provide a step-by-step guide to cord assessment in the delivery room setting. Pictures showing normal, atypical, and abnormal umbilical cords and common abdominal wall defects will be presented along with a brief discussion of the significance and clinical implications of each of these findings.