Single umbilical artery in twin pregnancies

European association of perinatal medicine (EAPM) position statement: Screening, diagnosis and management of congenital anomalies of the umbilical cord

Congenital anomalies of the umbilical cord are associated with an increased risk of pregnancy and perinatal complications. Some anomalies of the cord have a higher prevalence than other fetal structural anomalies. The most common anomalies are the absence of an umbilical artery and velamentous insertion of the cord (with or without vasa previa). These anomalies, even when not associated with fetal structural defects, increase the risk of adverse perinatal outcome including, fetal growth restriction and stillbirth. In the absence of prenatal diagnosis, vasa previa is associated with the highest perinatal morbidity and mortality of all congenital anomalies of the umbilical cord. Most cases can be detected by ultrasound from the beginning of the second trimester and should be included in the routine mid-pregnancy ultrasound examination. Documentation should include cord insertion site, number of vessels in the cord, and if other pathologies have been detected. Pregnancies at increased risk of velamentous cord insertion should be screened for vasa previa using transvaginal ultrasound and colour Doppler imaging. If a velamentous cord insertion or isolated single umbilical artery is detected, individualised follow-up during pregnancy and tailored obstetric management are indicated.

Incidence of congenital heart disease in fetuses diagnosed with single isolated umbilical artery. Systematic review and meta-analysis

OBJECTIVE

To estimate the proportion of heart disease in fetuses with a prenatal diagnosis of a single isolated umbilical artery.

METHODS

We performed a search strategy in MEDLINE (OVID), EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception to the present. We assessed the risk of bias and performed a meta-analysis. We completed the subgroup analysis according to the region.

RESULTS

We found 1384 studies by the search strategy. After carefully reviewing the full-text, 15 studies were included. A total of 2008 fetuses with a single isolated umbilical artery were included, and 177 had cardiac malformations. There was an overall incidence of 9% 95%CI (0.05-0.14) I2 90%. The incidence by country of origin was between 5% and 19%. The most common heart disease reported was a ventricular septal defect. Seven studies were found describing 25 cases. We described other malformations, such as tetralogy of Fallot, coarctation of the aorta, and hypoplastic left ventricle, among others.

CONCLUSION

The incidence of congenital heart disease in fetuses with a single isolated umbilical artery was high. In addition, half of these correspond to significant heart disease. Based on the above, we suggest that fetuses with a single isolated umbilical artery should have a complete anatomic evaluation emphasizing cardiac evaluation.

Prevalence of single umbilical artery, clinical outcomes and its risk factors: A cross-sectional study

Background

Single umbilical artery (SUA) is found in 0.5–6% of all pregnancies worldwide. Although the association of SUA with some congenital malformations is mainly accepted, its effect on pregnancy/neonatal outcomes is still controversial.

Objective

This is the first study aimed to approximate the SUA prevalence in southern part of Iran. SUA epidemiologic features accompanied by some of its effects on pregnancy/neonatal outcomes are investigated as well.

Materials and Methods

In this cross-sectional study, data from two referral centers in Southern Iran were analyzed. In total, 1,469 pregnancies, fetuses, and neonates were examined for epidemiological features associated with SUA. SUA was confirmed by pathological examination, while congenital anomalies were diagnosed by clinical, ultrasound, and echocardiographical examinations. Data on pregnancy outcome were recorded based on the patients' medical records.

Results

The prevalence of SUA was 3.47% (95% CI: 2.6–4.6%). Fetal anomalies including renal, cardiac, and other congenital anomalies, intrauterine fetal death, early neonatal death, low birth weight, low placental weight, and preterm birth were significantly higher in the SUA group (OR = 68.02, 31.04, 16.03, 3.85, 11.31, 3.22, 2.70, and 2.47, respectively). However, the maternal multiparity was lower in the SUA group (OR = 0.65; 95% CI: 0.44–0.98).

Conclusion

A significant association was observed between SUA and increased risk of intrauterine fetal death and early neonatal death, as well as low birth weight and preterm birth. Obstetrical history of the mother like parity was identified as an important predictor of SUA. Further investigations are suggested on risk stratification of neonates in this regard.

Double inferior vena cava in a monochorionic twin pregnancy with selective fetal growth restriction

Congenital anomalies of the infrarenal inferior vena cava (IVC) are well described in adult life, however, little information exists on their associations in fetal life. Here, we describe a case of a monochorionic diamniotic (MCDA) twin pregnancy complicated by selective fetal growth restriction (sFGR) with an incidental finding of a double IVC in one child. In fetal life, variants of the infrarenal IVC are strongly associated with heart defects, which might suggest haemodynamic alterations or genetic causes, even more so in our case with MCDA twins complicated by sFGR.

Incidental Fetal Ultrasound Findings: Interpretation and Management

Ultrasonography is a common component of prenatal care worldwide and is often used in early pregnancy to determine gestational age, number of fetuses, fetal cardiac activity, and placental location. Patients and their families may also consider ultrasonography a social event, as it provides confirmation and reassurance of a normal pregnancy. Ultrasound screening is typically scheduled in the second trimester to visualize fetal anatomy and confirm gestational age. Most ultrasound examinations are reassuring, but some incidentally identify structural anomalies and soft markers for aneuploidy, making it necessary for health care providers to correctly interpret these findings. The health care provider's ability to prepare patients prior to the ultrasound and deliver the necessary information needed to make informed decisions regarding any follow-up screening or diagnostic testing is critical to reducing parental anxiety. Preparation for the anatomic survey should include counseling for normal and abnormal findings. The ethical concepts of patient autonomy and shared decision making are used as a guide in providing this critical information and enabling informed choices during follow-up for incidental ultrasound findings.

Role of ultrasonography in the management of twin gestation

Twins represent 1%-2% of all pregnancies, yet continue to account for a disproportionate share of neonatal adverse events including neonatal intensive care admission, morbidity, and mortality. Ultrasonography is central to the proper diagnosis of the type of twinning. Ideally, ultrasonography is performed before 14 weeks of gestation to determine chorionicity and amnionicity. Correct identification of the chorionicity in a twin pregnancy facilitates proper counseling and management of the gestation, including ultrasonography follow-up. Herein, the different types of twinning are reviewed, together with the implications for ultrasonography monitoring of each specific type of twin gestation.

Anomalies of the placenta and umbilical cord in twin gestations

The frequency of twin gestations has increased over the last few decades, mainly due to maternal age at childbearing, and the use of assisted reproductive technologies. Twins are at higher risk of aneuploidy, structural anomalies, and placental abnormalities. Some of the placental and umbilical cord abnormalities found in twin gestations are nonspecific and can be found in singleton gestations (ie, placenta previa, placental abruption, single umbilical artery, velamentous cord insertion, vasa previa, etc). However, other anomalies are unique to twin gestations, and are mainly associated with monochorionic twins-these include intraplacental anastomosis and cord entanglement. Most of these conditions can be diagnosed with ultrasound. An accurate and early diagnosis is important in the management of twin gestations. Determination of chorionicity, amnionicity, and the identification of placental anomalies are key issues for the adequate management of twin pregnancies. Pathologic placental examination after delivery can help in assessing the presence of placental and umbilical cord abnormalities, as well as providing information about chorionicity and gaining insight into the potential mechanisms of disease affecting twin gestations.

Congenital Malformations Associated With a Single Umbilical Artery in Twin Pregnancies

A single umbilical artery (SUA) was identified in 1.5% of twin pregnancies. The presence of a SUA in a twin pregnancy was associated with a 50% incidence of fetal anomalies, many of them complex and severe. The embryology and pathophysiological mechanisms associated with a SUA are reviewed. Aneuploidy is relatively common and should be considered, particularly in the presence of associated anomalies. Fetal growth restriction is frequent and preterm delivery is common.

Isolated single umbilical artery in twin pregnancies and its adverse pregnancy outcomes - a case report and review of literature

Single umbilical artery is the most common congenital abnormality of the umbilical cord and is seen in 4-11% of twin pregnancies. It is usually associated with intrauterine growth retardation, preterm labour, small-for-dates and other structural anomalies. There is no significant difference in the incidence between monochorionic and dichorionic twins. The left artery is usually absent more commonly than the right. The female co-twin was predominantly more affected than their male counterparts. Single umbilical artery is found twice more common in white women than in Afro-Asians and Americans. The hemodynamic disturbances occur early in the embryonic development, influence greatly in the development of single umbilical artery. Genetic and environmental factors also play a major role in the development of this anomaly. The pregnancies with single umbilical artery were classified as high risk group, because the overall perinatal mortality rate was estimated to be as high as 20%. There is a significant increase in the occurrence of single umbilical artery in pregnancies due to artificial reproductive technologies, as well as in spontaneous miscarriages. Prenatal ultrasonography is the principal diagnostic technique employed to identify single umbilical artery during 3(rd) trimester of pregnancy. The present case, reports the presence of a single umbilical artery in a monozygotic, monochorionic twin pregnancy, which is acardiac-acephalic fetus, small for dates, female sex, associated with other major structural anomalies, and was still born. Authors analyse its incidence, clinical presentations and pregnancy outcome and also review the pertinent literature.

Pregnancy prognosis associated with an isolated single umbilical artery in twin pregnancy

To determine the prognosis of an isolated single umbilical artery (SUA) in a twin pregnancy, we selected twin pregnancies with a second trimester ultrasound diagnosing a SUA in at least one fetus at our tertiary hospital. This was confirmed by placental histopathology or by expert review of ultrasound images. Cases were identified by searching the hospital ultrasound database over a period of 7.5 years. Higher order multiples or coexistent aneuploidy or major anomalies were excluded. Each case of an isolated SUA was assigned three consecutive twin pregnancy controls paired for chorionicity and maternal age. Primary outcomes were preterm birth <34 weeks, small for gestational age (SGA) or perinatal death. Other outcomes included antenatal growth restriction, mode of delivery, and admission to neonatal intensive care or special care nursery. Nine pregnancies (18 fetuses) were identified for analysis as cases. Isolated SUA was associated with preterm birth <34 weeks (odds ratio = 12.2; 95% CI = 2.0-75.2; p = .005) but not for SGA. There was also no difference in SGA between the affected twin and its normal co-twin. Perinatal death was increased but after controlling for gestational age and clustering this finding was no longer significant. We conclude that isolated SUA in twins adds a degree of risk to an already high-risk pregnancy but does not increase the need for surveillance for growth restriction.

The incidence of isolated single umbilical artery in twins and adverse pregnancy outcomes

OBJECTIVES

The aim of this study was to estimate the incidence of single umbilical artery (SUA) in twin pregnancies and to investigate whether SUA in twin gestations is associated with adverse obstetric outcomes.

METHODS

We performed a retrospective cohort study of consecutive twin pregnancies over 17 years at a tertiary care hospital. Primary exposure was SUA in one or both twins documented at routine second trimester anatomic survey. Adverse obstetric outcomes included small for gestational age (SGA), placental abruption, and preterm birth, evaluated in univariable and multivariable analyses. Analysis was performed both at the pregnancy level and at the fetal level using paired analyses to account for the non-independence of twin pairs.

RESULTS

Of the 2378 twin pregnancies without major anatomic abnormalities, 1.7% (n = 40) had SUA. Only one pregnancy (one monochorionic twin pair) was complicated by both twins having SUA. Twin fetuses with SUA are at increased risk for SGA (aOR = 2.1 (1.2-4.1), p = 0.03) after adjusting for pertinent confounding factors, similar to the findings of previous studies in singleton pregnancies. In addition, twins with SUA may be at increased risk for preterm delivery before 28 weeks compared with twin pregnancies with normal three-vessel umbilical cords (adjusted odds ratio (aOR) 3.2 (1.3-7.89.4), p = 0.01).

CONCLUSIONS

The incidence of SUA in twin gestations in this cohort is significantly less than the recently published data. Similar to reports in singleton gestations, SUA appears to be associated with an increased risk for SGA in twins.