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Pentalogy of Cantrell (PC) is a rare congenital syndrome involving the abdominal wall, sternum, diaphragm, pericardium, and heart. The embryonic period in which PC develops coincides with that of umbilical cord (UC) formation. The aim of the following study was to address the question of whether PC is associated with UC pathologies. Four cases, prenatally identified between 2002 and 2008, were enrolled in this study. Umbilical cord pathologies defined as single umbilical artery, short cord, or UC with atypical coiling pattern were retrospectively assessed on stored ultrasound images and from autopsy reports. The literature regarding PC and UC pathologies was reviewed. Three singleton pregnancies and 1 monoamniotic twin pregnancy with twin reversed arterial perfusion sequence were reviewed. All had a normal karyotype. Three showed the classical PC stigmata, with ectopia cordis. One fetus had no ectopia cordis; this case had a normal UC, whereas all others fetuses showed a short UC with atypical coiling pattern. Of 26 publications dealing with PC, the UC was described in only 8 cases, 7 of which were abnormal. There seems to be a strong correlation between the PC and UC abnormalities, in particular in cases with ectopia cordis. We speculate that the insult leading to the classical malformations of PC and UC abnormalities is the same or the sequence of malformations itself may alter the early fetoplacental blood flow and therefore the normal development of the UC angioarchitecture.

Objective: To determine whether a large cross-sectional area of the umbilical cord is a predictor of fetal macrosomia., Methods: Consecutive patients of > 34 weeks' gestation, who presented for sonographic examination and who delivered within 4 weeks of the examination, were included in the study. The sonographic cross-sectional areas of the umbilical cord, the umbilical vessels and the Wharton's jelly were measured in a free loop of the umbilical cord. Logistic regression analysis was used to determine significant predictors of macrosomia (actual birth weight > 4000 g and > 4500 g). Fetal biometric parameters (biparietal diameter, abdominal circumference and femur length), sonographic estimated fetal weight and umbilical cord area > 95(th) centile for gestational age were used as covariates., Results: During the study period, 1026 patients were enrolled. Fifty-three (5.2%) newborns had a birth weight > 4000 g, and 22 (2.1%) weighed > 4500 g. The proportion of cases with a large umbilical cord was significantly higher in the group of macrosomic compared with non-macrosomic infants (54.7% vs. 8.7%, P < 0.0001). Multiple regression models demonstrated an independent contribution of the large cord in the prediction of birth weight > 4000 g and > 4500 g (odds ratio (95% CI), 20.6 (9.2-45.9) and 4.2 (1.2-17.7), respectively). The sensitivity, specificity and positive and negative predictive values of a sonographic large umbilical cord were 54.7%, 91.3%, 25.4%, and 97.4%, respectively. The combination of abdominal circumference > 95(th) centile and large cord predicted 100% of macrosomic infants. The proportion of umbilical cords with a Wharton's jelly area > 95(th) centile for gestation was significantly higher in macrosomic fetuses of diabetic compared with non-diabetic mothers., Conclusions: Sonographic assessment of umbilical cord area may improve the prediction of fetal macrosomia.

Objective: Monochorionic twins with twin-twin transfusion syndrome (TTTS) provide an ideal model in which to evaluate the influence of differing hemodynamic stress on umbilical cord (UC) morphology. The purpose of this study was to investigate the UC morphometry and UC coiling pattern at ultrasound in monochorionic twin pregnancies with TTTS., Methods: A targeted sonographic evaluation of the UC was performed in 21 consecutive twin pregnancies with untreated TTTS. The cross-sectional area of the UC and of its vessels was measured. The Wharton's jelly area was computed by subtracting the vessels area from the area of the UC. The umbilical coiling index (UCI) was calculated as the reciprocal of the sonographic length of one complete vascular coil. The UCs were classified as uncoiled, normally coiled, hypocoiled, hypercoiled and atypically coiled (UCI not valuable)., Results: The UCs of recipient twins were invariably larger than those of donors, and this difference was mainly attributable to both a larger amount of Wharton's jelly and a larger umbilical vein diameter. The proportion of lean UCs was higher in the donor than in the recipient fetuses (18/21 vs 1/21, p < 0.0001), while large UCs were significantly more frequent in the recipient than in the donor twins (13/21 vs 1/21, p = 0.0002). In all twin pairs, a discordant umbilical coiling pattern was observed between the donor and the recipient twin. The prevalence of uncoiled and hypocoiled cords was higher in the donor group, while hypercoiling and atypical coiling were more frequently detected in the recipient group., Conclusions: A discordant UC morphometry represents an additional phenotypic feature of twins with TTTS. The discordant intertwin coiling pattern in TTTS argues against an exclusively genetic origin of UC twists, and further supports a key role of hemodynamic forces in coiling development., (2005 John Wiley & Sons, Ltd.)

The mechanisms by which the excess genetic material of chromosome 21 results in the dysmorphologic features of Down syndrome (DS) are largely unknown. It has been found that the extracellular matrix of nuchal skin of DS fetuses exhibits an higher content of hyaluronan (HA) compared to that of euploid fetuses. Since HA plays a central role in many morphogenetic processes during embryogenesis, an alteration in its metabolism could be involved in the pathogenesis of several structural defects of DS. The extracellular matrix of umbilical cord (UC) is the mammalian tissue with one of the highest content of HA. Therefore we sought to explore the quantitative HA modifications during gestation, tissue distribution and HA metabolism in euploid and DS UCs. Euploid UCs (n=28) and UCs from DS fetuses (n=13) were obtained after termination of pregnancy, spontaneous abortion, or at delivery. Quantitative and molecular size analysis were performed using HPLC and FPLC. Tissue distribution was visualized by immunohistochemistry. Gene expression for HA synthases (HAS) and hyaluronidases (HYAL) were quantified by real-time PCR techniques and HYAL activity was detected by zymography. In euploid UC only HA of a molecular weight of 1700 kDA was present while in DS UC an additional lower weight HA molecule of 1100 kDA was found. Immunohistochemistry showed a larger amount of Wharton's jelly HA in DS UCs than in euploid UC. Real-time PCR analysis showed that HAS 2 and HYAL 2 were expressed at significant levels in all specimens. A higher expression of HAS 2 and a lower expression of HYAL 2 was found in the Wharton's jelly of DS fetuses compared to that of euploid fetuses at 14 weeks of gestation. On the contrary, at term HYAL 2 expression was higher in DS specimens than in those from euploid fetuses. Zymographic studies showed a similar behavior with a lower HYAL activity at early gestation and a higher HYAL activity at term gestation in DS UCs compared to euploid specimens. Therefore we can conclude that HA is more represented in DS UCs than in euploid UCs. A complex alteration of the HA metabolism characterized by an increased synthesis of lower weight HA molecules is a peculiarity of DS UCs.

Objective: To investigate whether an atypical umbilical coiling pattern at prenatal sonography is associated with adverse pregnancy outcome., Methods: A targeted sonographic evaluation of the umbilical cord (UC) was performed in 758 women with singleton gestation, and gestational age above 20 weeks. Atypical coiling was defined as the presence of a spring-shape UC (supercoiling) or an unusual, aperiodic coiling pattern (uncoordinated coiling). Umbilical artery Doppler assessment was conducted in cases with atypical coiling. Pregnancy and neonatal outcomes were investigated., Results: Of the study population, 7 and 16 fetuses had an umbilical cord with uncoordinated coiling and supercoiling respectively. Three umbilical cords had a single umbilical artery. Eight patients delivered before 34 weeks of gestation. Eight fetuses were growth restricted. In seven cases, abnormal sonographic findings were detected (three meconium peritonitis, two severe hydronephrosis and two cardiac anomalies). One fetus affected by trisomy 18 presented multiple anomalies. Perinatal death occurred in three cases. Of the surviving newborns, eight were admitted to NICU. Umbilical artery Doppler waveforms presented a systolic notch in seven (30.4%) cases., Conclusions: The presence of an atypical umbilical cord vascular coiling is associated with an increased risk of unfavourable pregnancy outcome. The identification of an umbilical artery notch at Doppler investigation is frequently associated with an atypical UC coiling pattern., (Copyright (c) 2005 John Wiley & Sons, Ltd.)

Purpose: This study was undertaken to assess whether changes in umbilical cord vessel morphometry are associated with an increased risk of adverse perinatal outcome among fetuses with a lean umbilical cord on sonography., Patients and Methods: A total of 160 fetuses with a sonographically lean umbilical cord (cross-sectional area below the 10th percentile for gestational age) after 20 weeks of gestation were enrolled. The cross-sectional areas of the umbilical cord and its vessels were measured. Outcome variables investigated were perinatal death, admission to the neonatal intensive care unit, intrauterine growth restriction, and 5-minute Apgar score., Results: The proportions of perinatal death (1/96 versus 6/64, p < 0.05) and admission to the neonatal intensive care unit (17/96 versus 22/64, p < 0.05) was significantly higher among fetuses with an umbilical vein area below or equal to the 10th percentile for gestational age than among those with an umbilical vein area greater than the 10th percentile. No differences were found in the proportions of perinatal death, neonatal intensive care unit admission, 5-minute Apgar score < 7, and intrauterine growth restriction when fetuses with umbilical vein areas below or equal to the 10th, the 5th, and the 2.5th percentiles for gestational age were compared. No difference was found in the umbilical artery area and Wharton's jelly area among the groups., Conclusion: Among fetuses with a sonographically lean umbilical cord, a significant relationship exists between an umbilical vein area below or equal to the 10th percentile and an adverse neonatal outcome., (2004 Wiley Periodicals, Inc.)

Objective: To explore the sonographic vascular architecture and the hyaluronan amount and distribution of umbilical cords of healthy and trisomy 21 fetuses in early gestation., Material and Methods: Umbilical cord sonographic morphology and morphometry of 112 consecutive normal fetuses and 11 trisomy 21 fetuses were assessed between 10 and 15 weeks of gestation. The umbilical coiling index was defined as the reciprocal of the length of one complete coil measured in a longitudinal section of the umbilical cord. The umbilical coiling angle was defined as the maximum angle between the long axis of the umbilical cord and that of the umbilical arteries. Three umbilical cord samples obtained from Down syndrome fetuses and one from a healthy fetus after voluntary termination of pregnancy at 13 weeks of gestation were used for biochemical analysis. Quantitative hyualuronan content and tissue distribution was studied using fluorophore-assisted carbohydrate electrophoresis (FACE) analysis and staining methods using biotin-labeled hyaluronan-binding protein (bHABP), respectively., Results: A significant correlation was present between gestational age and both the umbilical coiling index (r=-0.56, p<0.001) and the umbilical coiling angle (r=-0.43, p<0.001). The proportion of uncoiled umbilical cords was significantly higher in Down syndrome fetuses than in healthy fetuses [8/112 (7.1%) vs. 4/11 (36.4%), p<0.05]. Biochemical analysis demonstrated a higher amount and a different distribution of hyaluronan in trisomy 21 umbilical cords compared to healthy fetuses., Conclusion: The umbilical cord of Down syndrome fetuses in early gestation shows peculiar sonographic vascular features and quantitative alterations of the Wharton's jelly hyaluronan.

Objective: To compare prenatal morphometric changes of umbilical cord components in intrauterine growth-restricted fetuses with and without abnormal umbilical artery Doppler parameters., Methods: Consecutive singleton intrauterine growth-restricted fetuses at a gestational age of older than 20 weeks were compared with matched appropriate-for-gestational-age fetuses. Intrauterine growth restriction was defined in the presence of a sonographic abdominal circumference below the 5th percentile for gestational age at the time of sonography and a birth weight below the 10th percentile. The sonographic examination included pulsed Doppler measurements of the umbilical artery resistance index and measurements of the umbilical cord cross-sectional area and the umbilical cord vessel area., Results: A total of 84 intrauterine growth-restricted fetuses and 168 appropriate-for-gestational-age fetuses were included in the study. All umbilical cord components (umbilical cord cross-sectional area, vein area, artery area, and Wharton jelly area) were smaller in the intrauterine growth-restricted fetuses. The prevalence of lean umbilical cords (cross-sectional area < 10th percentile for gestational age) was significantly higher in intrauterine growth-restricted fetuses compared with appropriate-for-gestational-age fetuses (73.8% versus 11.3%; P < .0001). A significant and progressive reduction of the umbilical vein area corresponding to the degree of umbilical artery Doppler parameter abnormality was found. The umbilical artery area was not related to the hemodynamic changes of the blood flow in the umbilical arteries., Conclusions: The proportion of lean umbilical cords was higher in intrauterine growth-restricted fetuses than in appropriate-for-gestational-age fetuses. Umbilical vein caliber decreases significantly with worsening of umbilical artery Doppler parameters.

Objective: To determine whether the sonographic morphometry of the umbilical cord components is different in preeclamptic compared with healthy pregnant women., Methods: Consecutive women admitted after 20 weeks' gestation with the diagnosis of preeclampsia and whose fetus was normally grown (cases) were included in the study. Each case was matched to a healthy pregnant woman (controls) who had ultrasonography at the same gestational age (+/- 3 days). The sonographic cross-sectional areas of the umbilical cord and umbilical vessels were obtained in all patients and plotted on reference ranges. The umbilical artery resistance index was measured in all patients with preeclampsia., Results: Twenty-five preeclamptic women were enrolled. The proportion of cases with a lean (below the tenth centile) umbilical cord was higher in cases than in controls (12 of 25 versus 1 of 25, P <.001). The Wharton's jelly area was lower in cases than in controls (median 105.8 mm(2) [range 49.6-212.9 mm(2)] versus 138.7 mm(2) [79.7-226.6 mm(2)], P =.024). The umbilical vein area was less in cases than in controls (median 29.2 mm(2) [range 8.0-52.8 mm(2)] versus 37.4 mm(2) [13.8-70.8 mm(2)], P =.032). The proportion of patients with a lean umbilical cord was higher among those with early-onset preeclampsia than in those with late-onset preeclampsia (12 of 19 versus 0 of 6, P =.014)., Conclusion: Early-onset preeclampsia frequently is associated with reduced Wharton's jelly area and umbilical vein area compared with normal pregnancy. Sonographic umbilical cord morphometry might have clinical value for prompt identification of women at risk for preeclampsia.

Objective: To compare the umbilical cord diameter at 10-14 weeks of gestation of chromosomally normal and abnormal fetuses., Methods: In a consecutive series of women, who were undergoing routine sonographic evaluation at 10-14 weeks of gestation, umbilical cord diameter and nuchal translucency were measured. Reference ranges for umbilical cord diameter according to gestational age and crown-rump length were constructed. Fetal karyotype was obtained at chorionic villus sampling, amniocentesis or at delivery in newborns with features suspicious for chromosomal abnormalities., Results: During the study period, 784 patients met the inclusion criteria. Of these, a fetal or placental chromosomal abnormality was present in 17 cases. The mean umbilical cord diameter increased with gestational age (r = 0.41, P < 0.001). The proportion of fetuses with an umbilical cord diameter above the 95th centile was higher in the presence of fetal or placental chromosomal abnormalities than in normal fetuses (5/17 vs. 39/767, P < 0.01). Among fetuses with an abnormal fetal or placental karyotype, nuchal translucency was above the 95th centile for gestational age in 10 cases. When only fetal chromosomal abnormalities were considered (n = 14), the combined detection rate was 85.7%(12/14)., Conclusions: Sonographic assessment of the umbilical cord in early gestation appears to identify a subset of fetuses at increased risk of chromosomal abnormalities.

Objectives: Experimental and clinical evidence have shown that the morphometry of the umbilical cord in the second half of gestation might be useful in predicting adverse perinatal outcome. The purposes of this study were to generate a nomogram for the umbilical cord diameter in the first trimester and, in an observational study, to investigate whether the sonographic measurement of the umbilical cord diameter early in gestation has the same clinical value as that late in gestation., Methods: The sonographic umbilical cord diameter, crown-rump length and biparietal diameter were measured in 439 fetuses at between 8 and 15 weeks of gestation. The perinatal outcome was recorded for all patients., Results: The umbilical cord diameter increased steadily from 8 to 15 weeks of gestation. A significant correlation was found between umbilical cord diameter and gestational age (r = 0.78; P < 0.001), umbilical cord diameter and crown-rump length (r = 0.75; P < 0.001) and umbilical cord diameter and biparietal diameter (r = 0.81; P < 0.001). No correlation was found between umbilical cord diameter values and either birth weight or placental weight. Among patients who had a miscarriage (n = 7) and pre-eclampsia (n = 8) the umbilical cord diameter was below 2 standard deviations from the mean in three cases (42.9%) and three cases (37.5%), respectively., Conclusion: The measurement of the umbilical cord diameter in the first trimester is correlated with the growth of the embryo and may be a marker for identifying a subset of fetuses at risk of spontaneous miscarriage and pre-eclampsia.

Objectives: To generate a nomogram for the sonographic measurement of Wharton's jelly area (WJA) during gestation and to investigate whether WJA is related to fetal biometric parameters., Method: The sonographic cross-sectional area of the umbilical cord and of its vessels was measured in 659 fetuses between 15 and 42 weeks of gestation. The WJA was calculated by subtracting the vascular area from the umbilical cord area. The conventional biometric parameters were measured and correlated with the WJA. Polynomial regression analysis was utilized for statistical purposes., Results: The WJA increased as a function of gestational age (r = 0.63, P < 0.001). The regression equation for the mean WJA (y) according to gestational age (x) was y = -114.7 + 4.142x - 0.01x2 and for the standard deviation (y') was y' = -7.567 + 1.319x. There was a strong correlation between the WJA and the umbilical cord area (r = 0.97, P < 0.001). A significant correlation was also found between the WJA and fetal biometric parameters before 32 weeks of gestation (WJA and biparietal diameter: r = 0.82, P < 0.001; WJA and abdominal circumference: r = 0.79, P < 0.001; WJA and femur length: r = 0.81, P < 0.001) while after 32 weeks of gestation no correlations were found between WJA and fetal anthropometric parameters., Conclusion: A nomogram for the WJA has been generated. The WJA increases as a function of gestational age and it is correlated with fetal size up to 32 weeks of gestation.

Traditionally, the prenatal assessment of the umbilical cord (UC) is limited to the assessment of the number of vessels and to the evaluation of umbilical artery blood flow parameters. Morphologic aspects of the UC have usually been studies by pathologists and retrospectively correlated with the perinatal outcome. The introduction of more sophisticated imaging techniques have offered the possibility to investigate the UC characteristics during fetal life from early to late gestation. A number of investigations have demonstrated that an altered structure of the UC can be associated with pathologic conditions (i.e. Preeclampsia, fetal growth restriction, diabetes, fetal demise). Nomograms of the various UC components have been generated and allow the identification of lean or large umbilical cords, entities frequently associated with fetal growth abnormalities and diabetes. A Wharton's jelly reduction has also been invoked as a possible cause of fetal death in the presence of single umbilical artery. Prenatal morphometric UC characteristics as well as arterial and venous blood flow parameters in normal and pathologic conditions will be discussed.

Objective: To evaluate whether umbilical vascular coiling is correlated with the umbilical vein blood flow profile and to investigate if this is different between fetuses with a lean and those with a normal umbilical cord., Methods: Consecutive women with a singleton gestation who delivered at term and who underwent an ultrasound examination within 24 h from delivery were studied. Umbilical cord and vessel areas were calculated. Umbilical vein blood flow parameters were obtained by digital color Doppler velocity profile integration. After delivery, the umbilical coiling index was calculated., Results: One hundred and sixteen women were studied. Twelve (10.3%) had a lean umbilical cord (area < 10th centile). A significant correlation was found between the umbilical coiling index and the umbilical vein blood flow (r = 0.67, P < 0.001). A significant difference between fetuses with and without a lean cord was found in terms of: umbilical coiling index (0.18 +/- 0.08 vs. 0.29 +/- 0.09, P < 0.005), cord area (87.6 +/- 5.1 mm2 vs. 200.6 +/- 34.6 mm2, P < 0.001), Wharton's jelly amount (25.7 +/- 10.3 mm2 vs. 122.1 +/- 33.4 mm2, P < 0.001), umbilical vein blood flow (93.7 +/- 17.8 ml/kg per min vs. 126.0 +/- 23.4 ml/kg per min, P < 0.001), and umbilical vein blood flow mean velocity (6.6 +/- 2.7 cm/s vs. 9.0 +/- 3.6 cm/s, P < 0.05). The proportion of fetuses with an umbilical vein blood flow < 80 ml/kg per min was higher when the cord was lean than when it was normal (25% vs. 1.9%, P < 0.01)., Conclusions: Lean umbilical cords differ from normal cords not only from a structural point of view but also in the umbilical vein blood flow characteristics. This could explain the increased incidence of intrapartum complications and fetal growth restriction among fetuses with a lean and/or hypocoiled cord.

Objective: To investigate whether the amount of Wharton's jelly in non-malformed fetuses with a single umbilical artery is different from that of fetuses with a normal umbilical cord., Methods: We evaluated patients with singleton pregnancies, non-malformed fetuses and single umbilical artery undergoing sonographic evaluation at a gestational age ranging from 19 to 41 weeks' gestation. The cross-sectional areas of the umbilical cord and of the umbilical vessels were measured. The amount of Wharton's jelly was calculated by subtracting from the total cross-sectional area of the umbilical cord the areas of the artery and of the vein. The umbilical cord cross-sectional area, the umbilical artery and vein areas as well as the amount of Wharton's jelly were plotted on previously published nomograms., Results: Twenty-two patients met the inclusion criteria. The umbilical cord cross-sectional area was within the normal range in 20 (90.1%) cases. The umbilical artery and vein areas were above 2 standard deviations from the mean in 20 cases and in 11 cases (50%), respectively. The amount of Wharton's jelly was below 2 standard deviations from the mean in all cases. An abnormal insertion of the umbilical cord (marginal, velamentous) was present in five cases (22.7%)., Conclusions: A reduction of Wharton's jelly is frequently present in cases of single umbilical artery. The increased perinatal morbidity and mortality observed in cases of single umbilical artery, even in the absence of congenital or chromosomal abnormalities, could be in part the consequence of a reduced amount of Wharton's jelly.

Objective: To determine reference ranges for the diameter and the cross-sectional area of the umbilical cord during pregnancy and to determine if umbilical cord morphometry is related to fetal size., Methods: A prospective cross-sectional study was designed to assess the sonographic cross-sectional diameter and area of the umbilical cord. The sonographic umbilical cord measurements were obtained in a plane adjacent to the insertion of the cord into the fetal abdomen. Nomograms for the umbilical cord diameter and area were computed. Fetal biometry included: biparietal diameter, abdominal circumference, and femur length. Polynomial regression analysis was conducted., Results: Five hundred and fifty seven patients were included into the study. The regression equation for the umbilical cord diameter (y) according to gestational age (x) was y=-10.0563+1.4265x+0.0194x2 and for the umbilical cord area (y') was y'=91.6-3.3x+0.03x2-0.00007x3. A significant relationship was found between umbilical cord measurements and fetal anthropometric parameters., Conclusion: Reference ranges for umbilical cord diameter and area have been generated. The sonographic diameter and cross-sectional area of the umbilical cord increase as a function of gestational age and both diameter and area correlate with fetal size.

Objective: The purpose of this study was to investigate whether the prenatal diagnosis of a 'lean' umbilical cord in otherwise normal fetuses identifies fetuses at risk of being small for gestational age (SGA) at birth and of having distress in labor. The umbilical cord was defined as lean when its cross-sectional area on ultrasound examination was below the 10th centile for gestational age., Method: Pregnant women undergoing routine sonographic examination were included in the study. Inclusion criteria were gestational age greater than 20 weeks, intact membranes, and singleton gestation. The sonographic cross-sectional area of the umbilical cord was measured in a plane adjacent to the insertion into the fetal abdomen. Umbilical artery Doppler waveforms were recorded during fetal apnea and fetal anthropometric parameters were measured., Results: During the study period, 860 patients met the inclusion criteria, of whom 3.6% delivered a SGA infant. The proportion of SGA infants was higher among fetuses who had a lean umbilical cord on ultrasound examination than among those with a normal umbilical cord (11.5% vs. 2.6%, p < 0.05). Fetuses with a lean cord had a risk 4.4-fold higher of being SGA at birth than those with a normal umbilical cord. After 25 weeks of gestation, this risk was 12.4 times higher when the umbilical cord was lean than when it was of normal size. The proportion of fetuses with meconium-stained amniotic fluid at delivery was higher among fetuses with a lean cord than among those with a normal umbilical cord (14.6% vs. 3.1%, p < 0.001). The proportion of infants who had a 5-min Apgar score < 7 was higher among those who had a lean cord than among those with normal umbilical cord (5.2% vs. 1.3%, p < 0.05). Considering only patients admitted in labor with intact membranes and who delivered an appropriate-for-gestational-age infant, the proportion of fetuses who had oligohydramnios at the time of delivery was higher among those who had a lean cord than among those with a normal umbilical cord (17.6% versus 1.3%, p < 0.01)., Conclusion: We conclude that fetuses with a lean umbilical cord have an increased risk of being small for gestational age at birth and of having signs of distress at the time of delivery.

Objective: To evaluate the clinical significance of the antenatally detected discordant umbilical arteries (UAs)., Methods: Women with singleton gestations undergoing sonographic evaluations were examined for the presence of discordant UAs. Transverse and longitudinal diameters as well as the area of both UAs were measured. Doppler flow velocity waveforms were recorded from both arteries. Macroscopic and microscopic examination of the umbilical cord was performed after delivery and the area of each artery was measured. Mann-Whitney U test and Spearman rank correlation were used for statistical purposes., Results: Data are presented as median (range). Discordance between UAs was found in 14 of 1012 women who underwent sonographic examinations. The vessel diameters and areas differed significantly between the discordant UAs (diameter 2.9 [1-4.3] versus 4.5 [3.8-6.5] mm, P < .001; area 6.6 [0.78-14.5] versus 16.25 [11.33-33.16] mm2, P < .001). A significant difference between UA size was confirmed after delivery (area 1.68 [0.9-3.06] versus 4.17 [1.12-13.8] mm2, P < .005). The difference in the area of the UAs in utero and at microscopic examination correlated significantly (r = .94, P < .05). In all cases, the resistance index was higher in the smaller artery than in the larger artery (0.71 [0.59-0.8] versus 0.6 [0.48-0.75] P < .01). Abnormal insertion of the umbilical cord or an abnormality of the placenta was present in eight cases. Perinatal death occurred only in a trisomic infant born at 24 weeks' gestation., Conclusion: The clinical significance of discordant UAs is that newborns are generally in good condition at birth and placental anomalies are common in this group of parturients. Abnormal Doppler velocimetry of the smaller UA should be taken with caution, because it does not seem to be associated with poor perinatal outcome.

Objective Our purpose was to evaluate the antenatal incidence of single umbilical artery (SUA) in twin pregnancies according to chorionicity and to assess its relationship with outcome. Methods Consecutive twin pregnancies undergoing ultrasound evaluation at our institutions were included. A targeted sonographic evaluation of the umbilical cord and vessels was performed in all cases. Chorionicity was determined according to standard ultrasound criteria. Results A total of 174 twin pregnancies, 100 dichorionic (DC) and 74 monochorionic (MC), were included in the study. An SUA was identified in 17 (9.8%) pregnancies, and in 18 (5.2%) fetuses. No difference was found in the incidence of SUA in DC and MC twins. Among affected pregnancies, all but one DC twin pregnancy were discordant for SUA. Structural and/or chromosomal abnormalities were present in 27.8% of fetuses with SUA. The prevalence of small-for-gestational-age fetuses and of discordant birth weight (> 20% discordance) was higher in the SUA group than in the rest of the population, although these differences were not statistically significant. Twin pairs discordant for SUA had significantly higher weight discordance than those with normal umbilical cords. The sonographic cross-sectional area of the SUA did not appear to show the typical adaptive dilatation usually seen in singleton pregnancies with SUA. Conclusions The incidence of SUA in twins is higher than in singletons, with no difference between MC and DC twins. Intrapair discordance for SUA in identical twins provides evidence against an exclusively genetic origin of this anomaly. The apparent failure of compensatory dilatation of the umbilical artery in twins with SUA may explain in part the higher risk for fetal growth restriction in these cases. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]