Single umbilical artery: review of 12 cases

The umbilical cord normally consists of three vessels, two arteries and one vein. The absence of one umbilical artery or single umbilical artery (SUA) has been associated with some adverse perinatal events, such as low birth weight, prematurity, congenital malformations and perinatal mortality. The authors present 12 cases of SUA confirmed by histologic examination and the principal maternal and perinatal features of these cases are analyzed. In our study there were a prematurity rate of 58%, a low birth weight rate of 66% and a perinatal mortality rate of 580/1000. Among our patients, 42% of the infants with SUA had major congenital malformations. An accurate examination of the umbilical cord at delivery is suggested, mainly because SUA is an important index to detect associated congenital malformations.     

Perinatal results following the prenatal ultrasound diagnosis of single umbilical artery

OBJECTIVE. To study the perinatal results in our population, following the prenatal ultrasound diagnosis of a single umbilical artery (SUA), as this alteration is associated with fetal malformations, chromosomal abnormality, and poor perinatal results. MATERIALS AND METHODS. A retrospective review of all obstetric ultrasounds carried out between October 2000 and December 2003 in our service, obtaining the postnatal results of the fetuses diagnosed with an SUA. RESULTS. From a total of 5,987 pregnant patients examined by ultrasound scan at 20th week, an SUA was found in 40 cases, representing an incidence of 0.7%. Of these, 84.6% were normal pregnancies at birth and 15.4% presented other malformations and/or chromosomal abnormalities. No aneuploidy was found in pregnancies where there were no other associated findings in the ultrasound scan at 20 weeks. All cases with serious congenital malformations accompanying the SUA were diagnosed prenatally. There was a 5% of perinatal mortality rate among our fetuses with SUA, which represents a mortality rate 10 times greater than the overall rate among our patients. CONCLUSIONS. The ultrasound discovery of an SUA implies the meticulous search for other associated malformations, and in the absence of these, the risk of a chromosomal abnormality is very low, unless it is a high-risk patient. However, the growth and wellbeing of the fetus must be carefully monitored in the last 3 months, although the ultrasound scan does not show any other associated alterations.     

Anomalies of the fetal venous system: a report of 26 cases and review of the literature

OBJECTIVE: To evaluate sonographic appearance, natural history, and neonatal outcome of fetal venous anomalies. METHODS: We performed an observational study, including all fetuses affected by abnormalities of the venous system diagnosed by ultrasound during the prenatal period. RESULTS: 26 fetuses were identified. Other malformations were present in 5 cases (19.2%), 1 fetus had trisomy 21, and 1 fetus had intrauterine growth retardation (IUGR). Twenty-five pregnancies ended in liveborn infants, and there was 1 case of unexplained intrauterine death in the fetus with IUGR affected by varix of the umbilical vein. CONCLUSIONS: Fetal venous anomalies are very rare and may be associated with fetal malformations or IUGR. Conservative management appears to be an adequate medical practice in the absence of other fetal problems, but in the presence of a varix of the umbilical vein, serial follow-up scans are needed to exclude the onset of hydrops or thrombosis of the varix.     

产前超声诊断单脐动脉与胎儿异常的相关性研究

目的探讨超声检测胎儿脐带血管数目预测胎儿先天异常的价值。方法2000年1月至2006年10月在中山大学附属第一医院采用超声检测胎儿脐血管数目，对单脐动脉胎儿行产前超声系统筛查及胎儿染色体检查；分析单脐动脉合并畸形类型，与染色体异常的关系及胎儿结局。结果产前超声诊断胎儿单脐动脉119例，包括左侧72例（60．5％），右侧47例（39．5％）。单纯性单脐动脉59例（49.6％）；合并其他结构畸形60例（50．4％），其中泌尿系统畸形25例（41．7％），心血管系统畸形17例（28.3％），中枢神经系统畸形15例（25.0％），下肢畸形9例（15．0％），前腹壁和消化道畸形各5例（各占8．3％），唇裂或唇腭裂畸形3例（5．0％），其他畸形3例（5．0％）。行胎儿染色体检查41例，发现染色体异常8例，包括18-三体综合征3例、13-三体综合征1例、21．三体综合征1例、染色体片段异常3例，均合并其他畸形。结论胎儿单脐动脉左侧发生率高于右侧，约50％合并其他畸形；合并畸形时，染色体异常发生率较高；大部分单纯性单脐动脉胎儿结局良好。     

Single umbilical artery: what does it mean for the fetus?

Single umbilical artery (SUA) is the most common anomaly of the umbilical cord which affects between 0.5 and 2.5% of all pregnancies. AIM: Our purpose was to determine whether there was a significant relationship between SUA and other anatomical anomalies. MATERIAL AND METHODS: All cases of fetal single umbilical artery identified in our hospital between 2002-2005 were reviewed for other ultrasound detected abnormalities. RESULTS: 18 cases of single umbilical artery were diagnosed on the basis of initial sonograms. 17 cases formed the study population (in 10 cases the left artery and in 7 the right artery was absent). In one case we diagnosed an umbilical cord tumor. 33.3% had other anatomical anomalies. The mean of women in the study was 30.5 years, the mean gestational age at examination was 28 weeks. CONCLUSIONS: In most cases the SUA occurs to be an isolated anomaly. In cases of SUA, the detailed ultrasound examination should be performed. Left artery absence is more common and also in these cases other anatomical anomalies are more likely to be observed as well. In our study we did not find a correlation between SUA and IUGR.     

Congenital anomalies: an increasingly important cause of mortality and workload in a neonatal intensive care unit

With improvement in perinatal management and advances in neonatal intensive care, congenital anomalies have emerged as a major cause of neonatal mortality and morbidity. A 1 year review (1985) of all the admissions to our neonatal intensive care unit (NICU) showed that 78 of 790 (10%) had one or more congenital anomalies. Of these, 26% died in the NICU; another 10% died during the first year; therefore the total mortality of infants with congenital anomalies in the first year of life was 36%. Even though they accounted for only 10% of the total admissions, the infants with congenital anomalies were responsible for 13% of the total NICU patient-days, 26% of the total NICU mortality, 32% of all deaths within the first year, and 35% of all NICU infants with intrauterine growth retardation (IUGR). Of interest, 67% of the infants with anomalies were suspected or diagnosed prenatally. Of these, 54% were delivered by cesarean section, done for fetal reasons in the majority of cases. The highest mortality was associated with (1) multiple abnormal prenatal ultrasound findings; (2) extreme prematurity (less than 30 weeks gestation); and (3) the presence of IUGR. These findings raise concerns about the use of resources in the management of the pregnancy and the delivery of infants with congenital anomalies, particularly when diagnosed prenatally.     

Single umbilical artery: prenatal findings

In 450 patients with pregnancy at high risk for fetal malformation and/or intrauterine growth retardation, the umbilical cord was investigated sonographically for the presence of a single umbilical artery. A single umbilical artery was diagnosed in four fetuses between 23 and 33 weeks of gestation and suspected in two. Three cases were overlooked at sonography. All seven surviving fetuses had growth retardation at delivery and four also showed severe malformations. Whenever a single umbilical artery is found at sonography, further work-up is required to rule out associated anomalies, intrauterine growth retardation, or chromosomal abnormality.     

Prenatal sonographic diagnosis of single umbilical artery: Emphasis on the absent side and its relation to associated anomalies

ObjectiveTo determine the absent side of a single umbilical artery (SUA) and to evaluate whether associated anomalies are related to the side of the missing artery in a Taiwanese population.Materials and methodsWe retrospectively studied SUA fetuses from our computer database of fetal ultrasound in a tertiary medical center in Southern Taiwan. All cases were diagnosed as SUA prenatally using conventional scanners of two- and three-dimensional (2D and 3D, respectively) ultrasound, as well as color, power, and high-definition Doppler. The absent side of UA and associated anomalies were analyzed.ResultsFrom September 2006 to November 2011, 31 fetuses with SUA were diagnosed prenatally by ultrasound and all were enrolled for this series. The incidence was estimated to be 1:556 (0.18% = 31/17,086). The mean maternal age was 29.2 years (range, 15–36 years) and the mean fetal age was 30.0 weeks of gestation (range 18–36 weeks). Notably, the left-absent UA was detected in 16/31 (52%) fetuses, compared with the right-absent UA in 15/31 (48%) cases. In addition, congenital anomalies were noted prenatally in 2/16 (13%) fetuses with left-absent UA and in 3/15 (20%) fetuses with right-absent UA.ConclusionIn SUA fetuses, the absence of UA appears to occur equally at each side. Moreover, this study showed no significant difference between either side of missing UA and associated anomalies after statistical examination.     

Single umbilical artery--consequences of prenatal diagnosis]

The authors report about the prenatal diagnosis of 34 cases of fetuses with a single umbilical artery (SUA) observed at the Perinatal Center of Charité. Between January 1989 and June 1991 the SUA has been associated with some adverse perinatal events, such as low birth weight (35%), congenital malformations (35%), perinatal mortality (11%) and placental alterations (76%). The incidence was not higher in girls than in boys. We did not find any chromosomal anomalies in our cases. An accurate ultrasonographic examination of the SUA in the 16th to 20th week is very important. The prognosis of the newborn could be improved by efficient diagnosis and optimum management of pregnancy and of delivery at a perinatal center.     

''Isolated'' single umbilical artery: incidence, cytogenetic abnormalities, malformation and perinatal outcome

AIM: The aim of the study was to 1) evaluate the gestational age at diagnosis and the incidence of single umbilical artery in an unselected population of 3750 pregnant women; 2) identify its association with malformations and/or karyotype aberrations in pre/postnatal age; 3) evaluate the fetal-neonatal outcome; 4) investigate the likelihood that a fetus might be affected by a cytogenetic abnormality even in presence of an apparently 'isolated' single umbilical artery. METHODS: Transabdominal ultrasound of the umbilical vessels and histological confirmation at birth. In presence of single umbilical artery an accurate prenatal ultrasound assessment, karyotyping (pre/postnatal), and clinical follow-up after birth were performed. RESULTS: The incidence of single umbilical artery in our population resulted 1.07% (40/3750), being 'isolated' in 40% of cases. The diagnosis of chromosomal aberration associated with single umbilical artery was made in 6 cases (15%), while structural fetal abnormalities in absence of causal chromosomal anomalies were present in 9 cases (22.5%), with syndromic patterns in 3 of them. In 2 cases with chromosomal anomalies the single umbilical artery was apparently 'isolated' at the ultrasound examination between the 17th and the 22nd week of gestation. Excluding 4 terminations of pregnancy, the perinatal mortality percentage resulted 25% (9/36); similarly, fetal growth retardation was present in 25% of cases (9/36). CONCLUSIONS: The incidence of single umbilical artery in our population confirms that this fetal vascular anomaly is frequently identified in pregnancy. In the light of our cases and data in the literature it is evident that diligent surveillance in prenatal age and accurate clinical follow-up after birth are mandatory when a single umbilical artery has been diagnosed. Finally, the possibility, even if rare, that even when the single umbilical artery is apparently 'isolated', a chromosomal aberration might be present (1/24 of our 'isolated' cases) should be considered when addressing correct counselling to the couples.     

Pregnancy outcome in isolated single umbilical artery

Our objective was to determine whether the rate of small for gestational age (SGA) infants and adverse perinatal outcome are increased in pregnancies diagnosed with an isolated single umbilical artery (SUA). We compared 297 pregnancies with a SUA diagnosed on routine obstetrical ultrasound with 297 pregnancies with a three-vessel cord control. Pregnancies complicated by major fetal anomalies were excluded. The rate of SGA, fetal death, and neonatal outcomes were compared between the two groups. Data analysis were performed using the T-test and chi-square test. The sample size had 80% power to detect a 50% difference between groups assuming a SGA rate of 20% in the SUA group and 10% in the control, alpha = 0.05. Among the SUA group, in 21 neonates (7.1%) the presence of a SUA could not be confirmed by postnatal examination, and 21 (7.1%) had major congenital anomalies, leaving 255 for final analysis. In the control group, 8 of the 297 (2.7%) had major congenital anomalies, leaving 289 for final analysis. The incidence of SGA neonates was 35 of 255 (13.7%) in the isolated SUA group compared with 38 of 289 (13.1%) in the control group ( P = 0.93). The composite perinatal outcomes (fetal death and/or SGA) were also similar between the groups (16.1% versus 14.5%; P = 0.72). We concluded that pregnancies with isolated SUA have a similar rate of SGA to those with 3VC.When a SUA is identified antenatally, a targeted ultrasound is warranted to rule out associated anomalies. Serial antepartum ultrasound for fetal growth is not necessary in managing pregnancies complicated by isolated SUA.     

A case of umbilical cord hemangioma: Doppler studies and review of the literature

Hemangiomas of the umbilical cord are extremely rare benign vascular tumors, not always detected prenatally. They have been associated with increased alpha-fetoprotein (AFP), hydramnios, congenital anomalies, and increased perinatal mortality. Impaired umbilical circulation has been proposed as the predisposing factor for fetal compromise. We report a case of an antenatally detected umbilical cord hemangioma with one artery crossing the tumor, and we reviewed the literature. Close surveillance with Doppler flow studies of the umbilical vessels were carried out throughout the pregnancy. All indices were normal, except from the intra-tumoral part of the umbilical artery under discussion that showed increasing resistance from 32 weeks onwards.     

Severe intrauterine growth retardation; assessment of its origin from fetal arterial flow velocity waveforms

Doppler blood flow velocity waveforms in the umbilical artery and fetal internal carotid artery were recorded in a total of 10 patients with severe intrauterine growth retardation (IUGR) and marked oligohydramnios to establish a fetal or utero-placental origin of IUGR. Gestational age varied between 28 and 37 wk. Negative maternal serology ruled out fetal infections. In six patients, IUGR was associated with abnormal flow velocity waveforms, indicating utero-placental insufficiency. Following delivery, these infants showed no structural defects; moderate to marked placental infarction was documented in 4 out of 6 cases. In the remaining four patients, IUGR was associated with normal flow velocity waveforms, suggesting a fetal origin of the IUGR. Following delivery, all four infants revealed structural defects, only one of which was diagnosed prenatally. Twice an abnormal karyotype was the underlying cause. There was no placental infarction. These preliminary data suggest that combined recording of the flow velocity waveform in the above-mentioned vessels may provide valuable additional information as to the cause of IUGR and as such be helpful in determining obstetric management.     

Doppler velocimetry in the fetus with a single umbilical artery.

OBJECTIVE: To study Doppler velocimetry in fetuses with a single umbilical artery (SUA) as compared to normal. STUDY DESIGN: Private and clinic patients were referred to a perinatal center: 45 with SUA and 124 randomly selected fetuses with a three-vessel cord were studied from 18 to 41 weeks' gestation. Color Doppler flow and energy were utilized to evaluate the umbilical arteries at the fetal abdominal wall as well as the course around the bladder. In addition to Doppler velocimetry, an anatomic survey, estimated fetal weight (EFW) and amniotic fluid index (AFI) were assessed at each examination. RESULTS: Doppler velocimetry in SUA demonstrated indices in the normal range but lower than in normal cords from 26 weeks until near term. Anatomic anomalies were found in 8.9% of SUA as compared to 4.8% for three-vessel cords. Intrauterine growth restriction (IUGR) was seen in four cases of SUA and none in the control group. EFW and AFI for both groups were virtually identical. CONCLUSION: SUA cords theoretically carry a normal blood volume, and the decreased resistance to flow and larger arterial diameter allow this to occur. Anomalies and IUGR are elevated in infants with SUA. Overall, EFW and AFI were the same in both groups of patients.     

Monoamnotic twin pregnancy. Multicenter study

OBJECTIVE: The purpose of this study was to evaluate of perinatal mortality and morbidity of monoamniotic twins. STUDY DESIGN: This was a multicenter retrospective analysis of 26 monoamniotic twin gestations identified between 1985 and 2004 in a 3 perinatal departments. Of these 26 pregnancies, 11 women were admitted electively for inpatient fetal monitoring. Overall mortality rates, the risk of intrauterine fetal death and neonatal mortality and morbidity, pregnancy complications and fetal anomalies were calculated. RESULTS: Monoamniotic twin pregnancies were diagnosed reliably prenatally by ultrasound in 22 women and at delivery in 4 cases. Of the 26 gestations, spontaneous fetal losses before 22 weeks of gestation were 4 cases. The overall loss rate and the perinatal mortality rate were 52% and 19.4%, respectively. Twenty-two women had both twins alive at 24 weeks of gestation; 11 women were admitted electively for inpatient fetal monitoring at 26-27 week of gestation. In this group there were 2 neonatal deaths. No intrauterine fetal death occurred in any hospitalized patient. In our series there were 100% incidence of prematurity, 38,5% of umbilical cord entaglement, 23% of TTTS, 3.6% of TRAP and 9.6% fetal congenital anomalies. CONCLUSION: Monoamniotic twins are at extremly risk of pregnancy complications and fetal loss. These pregnancies can be diagnosed reliably by ultrasound in most cases. Electively admitted women for inpatient fetal monitoring could be improved neonatal survival and decreased perinatal morbidity.     

Monoamniotic twins: diagnosis and management

Monoamniotic twins, although uncommon, are associated with high antenatal and perinatal morbidity and mortality. The associated complications include cord entanglement, congenital anomalies, twin-twin transfusion syndrome, intrauterine growth retardation and preterm delivery. A thorough literature search using Medline and OVID was performed to look at the current diagnostic criteria for monoamniotic twins and the subsequent management. Specific criteria are employed during ultrasonography for making the diagnosis. Different opinions in the literature exist regarding the proper antepartum monitoring of monoamniotic twins, the optimal timing and the mode of delivery. Generally, it is agreed that there should be regular antepartum fetal heart trace monitoring and serial sonograms with umbilical artery Doppler flow study. Most studies advocate delivery at 32 weeks to reduce the risk of intrauterine deaths related to cord entanglement. Cesarean section is the preferred mode of delivery even though cases of successful vaginal delivery have been reported.     

Lymphangioma--prenatal and perinatal aspects--Part one

Lymphangioma or cystic hygroma is a congenital malformation of the lymphatic system which has been commonly associated with fetal aneuploidy, hydrops, structural malformations and intrauterine death. In this paper we would like to report two cases of lymphangioma diagnosed prenatally in the third trimester in the fetuses with normal karyotype, normal NT in the first trimester and without other structural anomalies and with good perinatal outcome.     

Umbilical arterial thrombosis with vascular wall necrosis: clinicopathologic findings of 11 cases

Thrombosis of umbilical cord vessels is associated with a high perinatal mortality. Most cases are venous thrombi, arterial thrombi are uncommon. To clarify clinical and pathological features of this entity, we reviewed 11 cases with umbilical artery thrombosis. The gestational ages were 33-40 (mean 36.8) weeks. Three cases (38%) were associated with severe intrauterine growth retardation and two cases (25%) led to intrauterine fetal deaths. All cases had completely occlusive thrombi of one umbilical artery. The arteries with thrombosis demonstrated partial necrosis of vascular wall. The pathogenesis is unclear, but nine cases (82%) had cord abnormalities (long cord, peripheral cord insertion, short cord with twist, funisitis). This paper is the first report of clinical and pathological features of umbilical artery thrombosis. The results of this study confirm the clinical importance and unique histological findings of umbilical artery thrombosis. The recognition of umbilical artery thrombosis is necessary to establish the diagnosis and treatment of this condition.     

Recent Advances in the Use of Doppler Waveform Indices in the Antenatal Assessment of Intrauterine Growth Retardation

Summary: Doppler ultrasound has been advocated as a useful tool to evaluate pregnancies with intrauterine growth retardation (IUGR). However, many previous studies have used smallness for gestational age (SGA) at birth to define IUGR. The ability of Doppler ultrasound to predict SGA, neonatal morphometric indices of wasting such as a low ponderal index, and perinatal morbidity is reviewed. Doppler assessment of the umbilical and uteroplacental vasculatures were inferior to ultrasound measurements of fetal size in the prediction of SGA. In low risk fetuses, umbilical artery waveform indices were of limited value in the prediction of neonatal morphometric indices of wasting. Within a group of high risk fetuses, Doppler assessment of the umbilical artery and, in particular, the middle cerebral and aortic vessels, were useful in predicting fetuses with neonatal wasting. Similar findings were noted in the prediction of perinatal morbidity. The review confirms the usefulness of umbilical artery Doppler waveform indices in the antenatal assessment of IUGR. Whilst preliminary studies appear to suggest that Doppler waveform indices of the middle cerebral and aortic vessels may confer an additional advantage in the antenatal assessment of IUGR, randomized controlled trials evaluating their effect on perinatal outcome and studies on the reproducibility of these indices need to be carried out before their widespread introduction into obstetric practice.     

Outcomes of an isolated single umbilical artery in singleton pregnancy: a large study from the Middle East and Gulf region

Objective

To assess the frequency and accuracy of prenatal diagnosis of a single umbilical artery (SUA) and to compare the fetal and neonatal outcome of isolated SUA to that of a normal three-vessel umbilical cord in a population from the Middle East and Gulf region.

Study design

Data were collected from 37,500 singleton pregnancies that were scheduled for antenatal care and delivered at Security Forces Hospital in Riyadh, Saudi Arabia, between May 2004 and December 2012. Comparisons between the groups were performed using a chi-square test or a Fisher exact test for the categorical variables, and Student's t test or Wilcoxon's rank-sum test were used for continuous variables. The Kappa statistic was used to study the agreement between the antenatal and final neonatal diagnosis of SUA. A univariable analysis was used to calculate the unadjusted and adjusted ORs and the 95% CIs expressing the relationship of the normal three-vessel umbilical cord, the isolated SUA, and each outcome.

Results

A total of 35,249 cases completed the study, including 35,026 cases with normal neonatal three-vessel umbilical cords (Group B). SUA was present in 223 (0.63%) neonates (0.45% isolated SUA (Group A) and 0.18% non-isolated SUA). The sensitivity, specificity, positive predictive value and negative predictive value of using prenatal ultrasound for the diagnosis of SUA were 90.58%, 99.9%, 98.5% and 99.94%, respectively. Neonatal anomaly was present in 2.6% of the fetuses with isolated SUA. A pregnancy with isolated SUA was more likely to be complicated with polyhydramnios (OR 3.32; CI 1.22–9.04), preterm delivery <34 weeks (OR 4.662; CI 2.346–9.195), birth weight <10th percentile (OR 2.1; CI 1.44–2.93), cesarean delivery for fetal distress (OR 2.72; CI 1.53–4.81), perinatal death (OR 3.31; CI 1.34–8.12), admission to NICU (OR 2.71; CI 1.87–3.91), and placental abnormalities (OR 3.25; CI 2.14–4.93; p value 0.0001) compared to a pregnancy with a fetal and neonatal three-vessel cord.

Conclusion

Isolated SUA is associated with anomalies at birth and with an increased risk of adverse pregnancy outcomes even in the absence of other anomalies. A pregnancy with this complication should receive close fetal monitoring for growth and fetal wellbeing.