J. V. K. Tan

The amniotic sheet: a truly benign condition?

Amniotic sheets are the result of uterine synechiae that have been encompassed by the expanding chorion and amnion. Radiologically they are seen as ‘shelves’ in the amniotic cavity. The benign nature of such amniotic sheets has been documented in many case series in the literature. The objective of this study was to determine the characteristics (if any) of amniotic sheets that predict fetal outcome.

OC061: A single‐centre review of antenatally diagnosed fetal echogenic kidneys

Introduction: Choroids plexus cysts (CPC) are important for their association with fetal aneuploidy, particularly trisomy 18, which some authors described almost 20 years ago. In spite of numerous works through the years a clear-cut link between trisomy 18 and CPC has not been found. Methods: We analyzed 16 272 patients referred to our centre from January 1998 to December 2002. Only the patients with a first examination between 16 and 23 gestational weeks were included. Fetuses with a CPC were checked for either an amniocentesis (amnio) or a normal outcome at birth. From the group of CPC extracted, fetuses with associated anomalies were noted. From the group with associated anomaly a group with minor and a group with major was extracted. Results: From the total, 366 had CPC, that is 2.9%, 311 had no other associated anomalies; either the karyotype or the postnatal pediatric examination was normal, 55 of the patients had associated anomalies, from this group 12 fetus with present major anomaly were extracted and in two cases the amnio revealed two cases of trisomy 18. The other 10 cases had normal karyotype. The 43 fetuses with CPC and minor finding had either a normal amniocentesis or pediatric examination at birth. In addiction, in the period of study we identified overall 6 fetuses with karyotypically proven trisomy 18. In the 4 fetuses with trisomy 18, the presence of major anomalies in absence of CPC, strongly suggests the performance of a karyotype. Conclusion: In the isolated CPC there is not evidence of aneuploidy. If the isolated CPC had been aggressively pursued the total fetal loss would have been increased to 1.55 fetus assuming a commonly quoted risk of 1 : 200 miscarriage. Another reason is that the trisomy 18 is considered uniformly fatal, there is another important factor to consider the exposure of healthy population at the karyotype risk for recognized a very small population with a very poor prognosis.

P15.05: Ultrasound features of an anomaly of the umbilico‐portal system—a case report

examination showed no further anomalies, especially no craniofacial, urogenital, heart or lung malformations. Therefore, our case concerned a Tetra-amelia, and not a tetra-Amelia syndrome. Tetra-Amelia syndrome is described to be caused by a homozygous WNT3-gene mutation in only one consanguineous family. DNAanalysis of this gene was therefore not performed. The autosomal recessive Roberts syndrome is characterized by tetraphocomelia and is clinically variable. DNA-analysis of the ESCO2-gene was performed. No pathological mutations were found in this gene. In this case the couple was counselled for a low recurrence rate. Meanwhile, a new pregnancy occurred and the prenatal scan at 16 weeks showed normal limbs.

P03.05: Report of a case of right ductus arteriosus in a fetus with right aortic arch

Objectives: To evaluate the diagnostic accuracy of prenatal screening for congenital heart diseases (CHD) based on the combination of the four-chamber view and the three-vessel view in an unselected population. Methods: A prospective study on 8025 scanned fetuses was performed. All singleton pregnancies scheduled for a routine prenatal ultrasound screening at 20–24 weeks’ gestation and subsequently delivered within our unit were included. Data were recorded regarding visualization of the four-chamber view, the outflow tracts and the three-vessel view. Suspected CHD was confirmed by postmortem or postnatal echocardiography. We obtained the followup data of the newborns and calculated the diagnostic accuracy of the test. Results: Major CHD were identified in 32 cases (4.0‰) of which 26 cases (81.3%) were diagnosed antenatally and 6 postnatally. Four cases were false positive. Twenty-one cases were identified by the four-chamber view and five as a result of the abnormal three-vessel view. The sensitive of the four-chamber view alone was 65.6% (17/32), and the specificity was 99.9%. The sensitivity of the combination of the four-chamber view and the three-vessel view was 81.3% (26/32), and the specificity was 99.9%. Conclusions: The three-vessel view is reliable and easy methods to be used in a routine antenatal clinic, along with the four-chamber view. *This project was funded by Beijing Municipal Science and Technology Commission Foundation grant D0906005000091.

P03.08: Prenatally diagnosed interrupted IVC: a report of 2 cases

Case report: A 28-year-old woman, gravida 2 para 1, had routine second trimester ultrasound examination in our antenatal diagnostic center at 21.3weeks. We found a right aortic arch and right ductal arch on 3 vessel and trachea (3VT) view. The thymus was visualized. The rest of fetal structures appeared normal. A normal fetal karyotype (46,XX) was found, with no evidence of microdeletion of chromosome 22q on fluorescence in-situ hybridization. Patient delivered a female infant by vaginal birth at 36.7week’s gestation. After delivery, echocardiography was done, and moderate perimembranous ventricular septal defect was found. The baby was well and no complications were found. Conclusion: Right aortic and right ductal arch can be diagnosed prenatally, with the use of the 5 plane views of Yagel, especially with the 3VT view. Isolated right aortic arch and the right ductal arch is a benign vascular anomaly with no known postnatal complications. However, a detailed evaluation of the fetal cardiac structures and karyotying has to be considered due to its association with cardiac/non-cardiac malformations and microdeletion 22q11 syndrome. Right ductal arch is rare and should be diagnosed before ligation of PDA in the neonates.

P04.08: Right cardiac isomerism—a more common occurrence in Asian fetuses?

Introduction: Isomerism of the atrium is the result of a defect in lateralization associated with bilateral morphologically identical atrial appendages. It is commonly associated with gross cardiac and vascular anomalies. Many of the affected individuals die at an early age. Objective: To present our experience in the prenatal diagnosis of anomalies of cardiac isomerism using high-resolution color Doppler ultrasound. Methodology: There were 116,859 low-risk patients scanned in the Antenatal Diagnostic Center as part of their routine screening over a 8-year period from 1998 to 2005. A retrospective review of congenital heart disease (CHD) associated with isomerism was conducted. Results: A total of 36 cases of suspected isomerism were observed among the cases of CHD diagnosed. Isomerism was confirmed by postmortem or postnatal 2D echo in 22 cases. In eighteen out of twenty-two (82%) of these cases, a right-sided isomerism was noted. They typically presented with AVSD (11/18), dextrocardia (8/18), situs inversus (9/18) in antenatal scan. In two of them a large azygous vein was presented. Postmortem showed 3-lobed or 4-lobed lung bilaterally. In four left-sided isomerism cases, only one had azygous drainage of IVC. None of them associated with heart block. Karyotypes were done in 13 of 22 cases and were all normal. Conclusion: There is geographical heterogeneity in the presentation of isomerism. Right isomerism is exceptionally common in our local population. We postulate that there may be a racial predisposition to the presentation of the type of isomerism. There was also a low association with karyotype abnormality.

P01.17: Transposition of great vessels—a single centre review in an Asian population

Three underwent termination of pregnancy; multiple congenital abnormalities (14 + 1 weeks), recipient of twin–twin transfusion syndrome (TTTS) (17 weeks), and maternal choice (23 + 1 weeks). All showed tricuspid regurgitation (TR) with AREDF DV in the two older fetuses. Of the 11 continuing pregnancies, 10 had a reasonable RV at presentation, one with a large RV to coronary fistula, and 4 had tricuspid valve Z scores of > -3 at delivery, 2 with normal DV. TR was absent in 3: all had normal DV, unrestrictive oval foramen (OF) and TV stenosis (Z score < -3). Six of the 8 with TR showed intermittent AREDF DV, (2 were monochorionic diamniotic pregnancies without TTTS), 4 had associated TV stenosis and 2 restrictive OF. Conclusions: Waveform analysis of DV should be interpreted with caution in PA/IVS because it may imply increased right atrial pressure due to tricuspid regurgitation or restriction to right atrial emptying and not necessarily fetal hypoxaemia or acidosis.

P266: The uterine shelf—is it a prognosticator of poor fetal outcome?

Objective: To look at the correlation between uterine shelf characteristics and fetal outcome. Methodology: In this retrospective study, the hospital-based Birth Defect Registry was searched for cases of uterine shelves from January 2001 to December 2002. The characteristics of these shelves were studied ie. its site in the upper, middle or lower uterine segment, the shelf thickness and whether the shelves were complete or incomplete. The postnatal outcomes of these cases were then reviewed. Results: During this period, 44 cases of uterine shelves (44/30124 or 0.2%) were diagnosed among 30124 deliveries. 6 cases defaulted follow-up. 43.2% (18/44) had a history of previous dilatation and curettage and 15.9% (7/44) had previous caesarean section. 2 pregnancies ended with IUD at 34.5 and 37.1 weeks gestation (2/38 or 5.3%). In this group, the uterine shelves were complete, situated in the lower uterine segment and their average thickness was 3.3 mm. Among the 36 cases with good perinatal outcome, the uterine shelves were all incomplete and 61.1% (22/36) were situated in the lower uterine segment. Their mean shelf thickness was 3 mm. 22.2% (8/36) were also associated with preterm birth under 37 weeks’ gestation. Conclusion: We conclude that previous uterine surgery may be a risk factor for the presence of uterine shelves and that the presence of complete shelves in the lower segment of the uterus may be associated with adverse fetal outcome. Prospective studies with larger numbers are needed to evaluate this phenomenon further.

P059: Antenatal surveillance of fetal abnormalities—the importance of a population based Birth Defect Registry

Objective: To describe our experience in prenatal diagnosis of hemivertebra. Methods: The present study presents a case series of six consecutive cases identified among cases referred to our tertiary medical center over a three-year period. All fetuses were scanned by high-resolution real-time scanners. The apparent vertebral anomaly was assessed in real-time manner by a joint team of Obstetricians, Sonographers and Pediatric orthopedic surgeons. A complete anomaly survey of other fetal organs was performed on each fetus. All patients were given proper counseling by the same joint team. All patients had detailed obstetric and neonatal follow-up. Prenatal sonograms, neonatal medical records and clinical course were evaluated retrospectively. Results: During the period of 1999 and 2002, six cases of hemivertebrae were identified in our department. Gestational age at diagnosis was 14–23 weeks. Two patients conceived by ART. Associated anomalies and outcome are described in Table 1. Conclusion: Diagnosis of isolated hemivertebra is associated with favorable outcome. The three key factors in achieving an optimal spine at maturity – Early diagnosis, anticipation and prevention of deterioration might be enhanced by our joint multidiscipline approach to the diagnosis of skeletal anomalies.

P076: Gastrointestinal abnormalities in fetuses with echogenic bowel detected during the antenatal period

Objective: This study was undertaken to evaluate the feasibility of using free-hand three-dimensional (3D) ultrasonography to evaluate the volume of the fetal stomach. Material and methods: We studied a total of 108 normal singleton fetuses from 13 to 42 gestational weeks. During 2D ultrasonographic examination three-dimensional upper abdomen data were collected prospectively. The stomach was scanned with a fanning motion of the transducer in the axial plane, nearly parallel to the conventional abdominal circumference plane. 3D volume segmentation processing of the stomach was performed and saved in different files. Stomach volume was calculated. Results: In almost all cases in which the stomach was visualized it was possible to calculate structure volume. There was considerable volume variation during the range of gestational ages studied. This preliminary study would have to be expanded to construct nomograms of stomach dimensions. Conclusion: 3D echocardiography can provide estimates of fluid filled fetal organs’ volumes and can be used for nomogram construction.