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Objective: To evaluate the effectiveness of adding outlet views to the four chamber view in routine prenatal ultrasound screening for major congenital heart defects (CHD) as performed by trained sonographers, and to compare the procedure with current practice. Design and setting: Prospective observational study at a London teaching hospital. Participants and methods: 9277 women booked at a single institution (80% had first trimester nuchal translucency measurement) due to have routine fetal cardiac screening using the four chamber and outflow tract views at > 18 weeks of gestation. Main outcome measure: Identification of major CHD in chromosomally normal and abnormal pregnancies antenatally or postnatally. Results: There were 40 abnormalities (4.3/1000), of which 30 were chromosomally normal (3.3/1000). The overall antenatal detection rate was 75% (95% confidence interval (CI) 59% to 87%) and 70% (95% CI 51% to 85%) for euploid pregnancies. Abnormal cardiac views accounted for 70% of all prenatal diagnoses, 30% of which were made at ≤ 18 weeks. The sensitivity of cardiac views during the first scan at > 18 weeks was 52%. Of all patients undergoing nuchal translucency screening, 34 had major CHD, nine with increased nuchal translucency (26.5%). Factors influencing the results of this screening programme were training and audit of operators, adequate equipment for antenatal examination, ease of access, and low threshold for referral to specialised fetal echocardiography. Conclusion: Adding ventricular outlet views to the four chamber assessment of the heart at routine fetal anomaly scans at > 18 weeks is the most effective technique to detect CHD prenatally. The success of such a programme depends on an infrastructure committed to continuous in house training of obstetric ultrasonographers coupled with feedback from specialised fetal cardiologists, as well as adequate resource allocation to obstetric hospitals involved with antenatal screening.

Background Ultrasound imaging of the fetal ductus venosus is becoming increasingly commonplace in clinical practice. The true anatomical relationships of the fetal umbilical and portal venous systems have not been clearly defined due to paucity of published data on the relevant anatomy. This has led to confusing terminology when describing the fetal umbilical, portal and hepatic circulations. The aim of the present study was to examine and document the anatomy of the umbilical, portal and hepatic venous systems and to propose a standardized nomenclature. Methods This was a prospective study on 11 fetuses obtained from medical termination of pregnancies between 14 and 19 weeks of gestation. The liver was microdissected to expose the branching pattern and anatomical relations of the umbilical, portal and hepatic venous systems. Results A wide L-shaped venous confluence at the terminal end of the umbilical vein, termed the portal sinus, was identified. The portal sinus was connected to the right and left hepatic lobes, by the right and left intrahepatic portal veins, respectively. The extrahepatic portal vein drained into the portal sinus just before the origin of the right intrahepatic portal vein. The ductus venosus, a branchless straight vessel, originated from the portal sinus and ascended steeply in the direction of the diaphragm. Numerous small vessels draining the liver converged into three main hepatic veins, which open into the subdiaphragmatic vestibulum. Conclusion Based on detailed sequential anatomical dissection and clear illustrations, the present study documents the anatomy of the umbilical, portal and hepatic venous systems. Taking into account the embryological origin of the vessels, a new anatomically appropriate and simplified nomenclature of these venous systems is proposed. In clinical practice, the consistent use of the suggested terminology would allow collection of comparable data between units and enable operators to be confident of which vessels they are sampling by Doppler ultrasound.

Objectives To confirm the hypothesis that isolated cardiac echogenic foci at the second-trimester anomaly scan do not influence our current calculation of risk of trisomy 21 in individual pregnancies, which is based on maternal age and nuchal translucency thickness at 11–14 weeks. Design Observational study in a fetal medicine unit. Methods In a general pregnant population undergoing first-trimester nuchal translucency screening, data from 239 singleton pregnancies with isolated cardiac echogenic foci at the second-trimester anomaly scan were compared with those of a control group of 7449 pregnancies with normal anomaly scans. Prevalence of trisomy 21 was determined in both groups. Following the anomaly scan, the individual risks of trisomy 21 were calculated by adjusting the previous risk based on maternal age and first-trimester nuchal translucency. We assumed that echogenic foci did not alter each individual risk calculation. The expected number of cases of Down syndrome in both groups was then calculated from the sum of probabilities of each individual affected fetus. The observed number of cases was compared with the expected number in both study and control populations. Results There was no statistically significant difference between the prevalence of trisomy 21 in the study group (no cases) and in the control population (three cases). From individual risk calculations, observing no cases of trisomy 21 in the study group was the most likely event if echogenic foci did not increase the risk of this chromosomal abnormality ( P = 0.62). Conclusion The finding of isolated echogenic foci at the time of the 20 week-scan does not significantly change the risks of trisomy 21 if background risk and previous nuchal translucency measurements are taken into account in the individual risk calculation. We suggest that no further adjustments to risk should be used. Copyright © 2001 International Society of Ultrasound in Obstetrics and Gynecology

Objective To evaluate the effectiveness of nuchal translucency (NT) measurement in screening for major congenital heart disease (CHD) in chromosomally normal fetuses. Design A population based cohort study of all women having fetal NT measurement at 10–14 weeks of gestation in an unselected population over a 3-year period. The outcome measure was the identification of major CHD in chromosomally normal pregnancies either antenatally or postnatally. Results Major defects of the heart and great arteries were identified in 26 out of 7339 pregnancies (prevalence 3.5 per 1000 pregnancies). Out of 26 cases, only four (sensitivity 15.4%, 95% CI 4–35) were in the group of 258 pregnancies (3.5%) with increased NT of ≥ 2.5 mm. The prevalence of major CHD increased from 3.1 per 1000 for NT < 2.5 mm to 50 per 1000 for NT ≥ 3.5 mm (likelihood ratio of 14.1, 95% CI 4.2–47.9). The positive and negative predictive values for NT ≥ 2.5 mm were 1.6% and 99.7%, respectively. Conclusions The prevalence of major CHD in this study was 3.5 per 1000, suggesting that ascertainment of CHD in our study population was thorough. Fetuses with NT measurements ≥ 3.5 mm have a significantly increased risk of major CHD, and this identifies a subgroup of high-risk patients in whom early fetal echocardiography would be advocated. The low sensitivity of NT for major CHD in the general population, however, indicates that NT cannot be relied on as the sole or major screening tool for this condition as previously reported. Copyright © 2001 International Society of Ultrasound in Obstetrics and Gynecology

Objective To determine the value of performing routine fluorescent in situ hybridization (FISH) for microdeletions of chromosome 22q11 when karyotyping fetuses with increased nuchal translucency. Design This was a prospective observational study carried out over an 18-month period. Fetal karyotyping by chorionic villus sampling was offered to 5429 women attending for a routine booking scan in the first trimester when their nuchal translucency adjusted risk for Down syndrome was ≥ 1 in 300. Cytogenetic samples were routinely tested for the 22q11 microdeletion when the nuchal translucency was ≥ 3 mm. Results The prevalence of increased nuchal translucency ≥ 2.5 mm was 180 (3.3%) and ≥ 3.5 mm was 42 (0.8%). None of 75 fetuses with an increased nuchal translucency and normal karyotype demonstrated a 22q11 microdeletion on FISH analysis. In the same cohort, 3 of 20 (15%) cases of major congenital heart defects in which nuchal translucency was measured, had a nuchal translucency measurement ≥ 2.5 mm. Conclusions Routine FISH analysis for chromosome 22q11 microdeletions at the time of chorionic villus sampling for increased first-trimester nuchal translucency is of limited value. As a significant proportion of fetuses with increased nuchal translucency will be found to have congenital heart defects later in the pregnancy, FISH analysis for chromosome 22q11 microdeletions can be targeted to fetuses with specific congenital heart defects. Tissue from the chorionic villus sampling should therefore be stored for subsequent analysis, until after detailed echocardiography is performed. Copyright © 2001 International Society of Ultrasound in Obstetrics and Gynecology

We report a case of the prenatal diagnosis of trisomy 8 in a fetus presenting with normal nuchal translucency of 0.8 mm and reversed end-diastolic ductus venosus blood flow at a routine first-trimester scan at 11 weeks of gestation. No structural abnormalities were detected by the ultrasound scan. Karyotyping by chorionic villus sampling led to the diagnosis of mosaic trisomy 8, which was confirmed by fluorescent in-situ hybridization on fetal tissue samples.

Background: Doppler of the fetal ductus venosus (DV) is becoming increasingly commonplace in clinical practice. However, the true anatomical relationships of the DV are yet to be clearly defined. Furthermore, there is conflicting evidence regarding the structure of the DV, especially with regard to the presence of a DV inlet sphincter. The aim of the present study is to examine the anatomy and morphology of the DV. Design: A prospective study on 24 fetuses obtained from medical terminations between 13 and 17 weeks' gestation. Following microdissection of the liver, specimens were prepared for study of the anatomical relations, scanning electron microscopy or histology. Results: A venous confluence at the terminal end of the umbilical vein, termed the portal sinus, was identified connected to the right and left intrahepatic portal veins. The DV, a branchless hourglass shaped vessel, originated from the portal sinus ascended steeply in the direction of the diaphragm. The endothelial surface of the DV showed longitudinal corrugations and at the level of the inlet, there was ‘shelf’ separating the DV from the portal sinus. Histological studies revealed elastin fibers, six to seven cell layers thick at the DV inlet and a single layer of smooth muscle extending from the shelf to the DV outlet. A large number of nerve fibers were present in the adventia of the DV inlet. Conclusions: This study clearly delineates the anatomical relations of the fetal ductus venosus. The morphological findings refute the presence of a DV sphincter, but provide an insight into the physiology of the human fetal DV. In clinical practice, the consistent use of the suggested appropriate terminology would allow collection of comparable data between units and enable operators to be confident of which vessels they are sampling by Doppler ultrasound.

Objective: To evaluate the role of ductus venosus (DV) Doppler in pregnancies with an increased nuchal translucency (NT) adjusted risk for the prediction of fetal outcome. Methods: Doppler assessment of the DV was performed in 124 fetuses with a first trimester NT-adjusted risk of >1:300 for Down syndrome. The pregnancy outcome, including karyo-type and structural abnormalities, were ascertained for all pregnancies. Results: The DV Doppler was abnormal in 27 (21.8%) pregnancies with an increased first trimester NT-adjusted risk. The outcome was normal in 69 pregnancies (55.6%). Thirty-nine pregnancies (39.5%) were aneuploid and further six pregnancies had adverse outcomes (three unexplained intrauterine deaths, two structural abnormalities and one major cardiac defect). The sensitivity of abnormal DV in this selected population was 51.3% for aneuploidy and 33.3% for adverse outcome. An abnormal DV Doppler increases the risk for aneuploidy by 11.8 (95% CI: 3.3–42.2). Conclusions: The finding of an abnormal DV Doppler signal increases the risk for aneuploidy 12-fold in a pregnancy with an increased NT-adjusted risk. Although DV Doppler can be used in addition to NT screening for aneuploidy, the sensitivity of DV Doppler is less than previously reported.

Background The aim of this study is to evaluate the effectiveness of routine antenatal screening for CHD in a routine obstetric population. Method A three-year prospective, observational study. All women were routinely offered first trimester nuchal translucency screening and an 18–23 week anomaly scan, where the four chamber view and outflow tracts were visualised. The main outcome measure was identification of major CHD in all pregnancies, either in the antenatal or postnatal period. Results Major defects of the heart and the great arteries were identified in 51 out of 9277 pregnancies. Major CHD were diagnosed antenatally in 42 fetuses and postnatally in nine (including 15 aneuploidies). The overall antenatal detection rate was 82.4% in all pregnancies and 80.6% in chromosomally normal pregnancies. In 10 cases, the first trimester NT measurement was increased. Conclusion The overall prevalence of major CHD (5.4/1000) suggests that ascertainment in the study population was thorough. The combination of first trimester NT screening and visualisation of the four-chamber/outflow tracts is effective in the detection of the majority of major CHD.