The antenatal diagnosis of placenta accreta.

The incidence of placental attachment disorders continues to increase with rising caesarean section rates. Antenatal diagnosis helps in the planning of location, timing and staffing of delivery. In at-risk women grey-scale ultrasound is quite sensitive, although colour ultrasound is the most predictive. Magnetic resonance imaging can add information in some limited instances. Patients who have had a previous caesarean section could benefit from early (before 10 weeks) visualisation of the implantation site. Current data refer only to placentas implanted in the lower anterior uterine segment, usually over a caesarean section scar.

Comparison of cardiac Z-score with cardiac asymmetry for prenatal screening of congenital heart disease.

OBJECTIVE: To determine the best screening tests for discriminating early indicators of cardiac hypoplasia in congenital heart disease (CHD) from normal variations in fetal cardiac growth. METHODS: We retrospectively examined fetal echocardiograms from 90 infants with confirmed CHD: Group 1 (n = 35) with right-sided obstructive lesions and Group 2 (n = 55) with left-sided obstructive lesions. Our control group comprised 2735 normal fetuses, from which we determined fetal cardiac Z-scores of right ventricle (RV), left ventricle (LV), aorta (Ao) and pulmonary artery (PA) diameters and ratios of right to left ventricle (RV:LV) and pulmonary artery to aorta (PA:Ao) size. We compared our control group to Groups 1 and 2 using ANOVA and area under receiver-operating characteristics curve (AUC) analysis. RESULTS: For Group 1, RV:LV ratio, RV-Z-score and PA:Ao ratio were the best screening tests, with highest AUCs (0.879, 0.868 and 0.832, respectively). For Group 2, the Ao-Z-score, PA:Ao and RV:LV ratios were the best screening tests, with AUCs of 0.770, 0.723 and 0.716, respectively. CONCLUSION: None of the screening tests was found to be a perfect early discriminator for the cardiac lesions tested. Although ratios of PA:Ao and RV:LV are useful, they should be combined with fetal cardiac Z-scores to maximize screening sensitivity.

Fetal echocardiography: z-score reference ranges for a large patient population.

OBJECTIVES: The main goal was to develop new z-score reference ranges for common fetal echocardiographic measurements from a large referral population. METHODS: A retrospective cross-sectional study of 2735 fetuses was performed for standard biometry (biparietal diameter (BPD) and femoral diaphysis length (FDL)) and an assessment of menstrual age (MA). Standardized fetal echocardiographic measurements included aortic valve annulus and pulmonary valve annulus diameters at end-systole, right and left ventricular diameters at end-diastole, and cardiac circumference from a four-chamber view of the heart during end-diastole. Normal z-score ranges were developed for these echocardiographic measurements using MA, BPD and FDL as independent variables. This was accomplished by using first standard regression analysis and then weighted regression of absolute residual values for each parameter in order to adjust for inconstant variance. RESULTS: A simple, linear regression model was the best description of the data in each case and correlations between fetal cardiac measurements and the independent variables were excellent. There was significant heteroscedasticity of standard deviation with increasing gestational age, which also could be modeled with simple linear regression. After this adjustment, the residuals conformed to a normal distribution, validating the calculation and interpretation of z-scores. CONCLUSION: Development of reliable z-scores is possible for common fetal echocardiographic parameters by applying statistical methods that are based on a large sample size and weighted regression of absolute residuals in order to minimize the effect of heteroscedasticity. These normative ranges should be especially useful for the detection and monitoring of suspected fetal cardiac size and growth abnormalities.

Maintaining quality assurance for sonographic nuchal translucency measurement: lessons from the FASTER Trial.

OBJECTIVE: To evaluate nuchal translucency measurement quality assurance techniques in a large-scale study. METHODS: From 1999 to 2001, unselected patients with singleton gestations between 10 + 3 weeks and 13 + 6 weeks were recruited from 15 centers. Sonographic nuchal translucency measurement was performed by trained technicians. Four levels of quality assurance were employed: (1) a standardized protocol utilized by each sonographer; (2) local-image review by a second sonographer; (3) central-image scoring by a single physician; and (4) epidemiological monitoring of all accepted nuchal translucency measurements cross-sectionally and over time. RESULTS: Detailed quality assessment was available for 37 018 patients. Nuchal translucency measurement was successful in 96.3% of women. Local reviewers rejected 0.8% of images, and the single central physician reviewer rejected a further 2.9%. Multivariate analysis indicated that higher body mass index, earlier gestational age and transvaginal probe use were predictors of failure of nuchal translucency measurement and central image rejection (P = 0.001). Epidemiological monitoring identified a drift in measurements over time. CONCLUSION: Despite initial training and continuous image review, changes in nuchal translucency measurements occur over time. To maintain screening accuracy, ongoing quality assessment is needed.

Craniomicromelic syndrome: a newly recognized lethal condition with craniosynostosis, distinct facial anomalies, short limbs, and intrauterine growth retardation.

We report on two sisters with an unusual form of craniosynostosis, protruding nasal spine, micrognathia, short limbs, lung hypoplasia, absent or hypoplastic gallbladder, short intestine with ileal distention, hypoplastic uterus, and intrauterine growth retardation. This combination of defects appears to be a newly recognized and probably autosomal recessive disorder.

Prenatal diagnosis of Smith-Lemli-Opitz syndrome, type II.

Smith-Lemli-Opitz syndrome, type II (SLOS-II) is a severe autosomal recessive disorder characterized by a distinctive face, unusual cleft palate, postaxial polydactyly, congenital heart defects, renal anomalies, and male pseudohermaphroditism. We present the first report of prenatal diagnosis of SLOS-II, as well as an additional report of prenatal detection of multiple anomalies, in which a positive diagnosis of SLOS II was made postnatally. In neither case was the pregnancy known prospectively to be at risk for SLOS-II. In the former case, targeted sonographic examination at 31 weeks of gestation showed intrauterine growth retardation, atrioventricular septal defect, mesomelic shortening of the arms, small kidneys, overlapping fingers, and female external genitalia; a 46,XY chromosome constitution had been ascertained previously. A provisional diagnosis of SLOS-II was made prenatally. In the latter case, targeted sonographic examination at 18 weeks of gestation showed severe oligohydramnios, atrioventricular septal defect, and Dandy-Walker malformation. The kidneys and bladder were not visualized. The chromosome constitution was 46,XX. The diagnosis of SLOS-II was made postnatally. In both cases, additional findings compatible with SLOS-II were noted postnatally. Prenatal detection of congenital heart defects and renal abnormalities, in combination with certain additional findings (most notably, female external genitalia in the presence of a 46,XY karyotype, polydactyly, disproportionately short limbs, or intrauterine growth retardation) and a normal karyotype, suggests the diagnosis of SLOS-II, and warrants further investigation.

Normal fetal heart axis and position.

Cardiac position and axis were evaluated by ultrasound in 183 normal fetuses; both position and axis were found to be constant throughout gestational life. In the four-chamber view of the fetal heart, the normal axis lies at a 45 degree angle (range 22-75 degrees) to the left of an anteroposterior line drawn from the spine to the anterior chest wall. The normal position of the posterior portion of the heart can also be defined. The axis or position of the heart deviated from the established normal range in 15 cases, the outcome of which is discussed. Abnormal axis was associated with 50% mortality; abnormal position with 81% mortality. Deviation from the normal position of the fetal heart should initiate a search for an intrathoracic mass, whereas an abnormal axis is an indication for fetal echocardiography. Axis and position of the fetal heart are easily evaluated during a standard obstetric scan.

Enlarged fetal cisterna magna: appearance and significance.

The differential diagnosis of a posterior fossa fluid collection in the fetus includes an enlarged cisterna magna, Dandy-Walker syndrome, or a posterior fossa cyst, each of which has differing implications for perinatal management. Causes of an enlarged cisterna magna include cerebellar hypoplasia, communicating hydrocephalus, and normal variation. Cerebellar hypoplasia is a frequent finding in the trisomies and therefore a careful search should be made for associated cardiac anomalies, growth retardation, and polyhydramnios.

Ultrasonographic left cardiac axis deviation: a marker for fetal anomalies.

OBJECTIVE: To determine if a relation exists between left cardiac axis deviation and fetal anomalies. METHODS: Estimation of cardiac axis was attempted prospectively as part of the cardiac examination in approximately 41,500 second- and third-trimester fetuses scanned between 1987-1993. Those with heart axes greater than 75 degrees to the left were considered to have left axis deviation. Only cases with postnatal follow-up were included. RESULTS: Thirty-four fetuses with left cardiac axis deviation had postnatal follow-up; eight were normal and 26 abnormal (positive predictive value 76%). Twenty-one fetuses had cardiac abnormalities (ten of these had additional extracardiac findings), and five had extracardiac findings only. CONCLUSION: Although left cardiac axis deviation can occur as an isolated sonographic finding in an otherwise normal fetus, most cases will demonstrate abnormalities of cardiac and/or extracardiac anatomy. Left cardiac axis deviation is largely associated with cardiac abnormalities, especially conotruncal anomalies, which may not be detectable by a four-chamber view alone. Therefore, the cardiac axis should be examined routinely as part of the four-chamber view of the fetal heart.

Interactive multimedia for prenatal ultrasound training.

This demonstration project examines the utility of interactive multimedia for prenatal ultrasound training. A laser-disc library was linked to a three-dimensional (3-D) heart model and other computer-based training materials through interactive multimedia. A testing module presented ultrasound anomalies and related questions to house-staff physicians through the image library. Users were asked to evaluate these training materials on the basis of perceived instructional value, question content, subjects covered, graphics interface, and ease of use; users were also asked for their comments. House-staff physicians indicated that they consider interactive multimedia to be a helpful adjunct to their core fetal imaging rotation. During a 9-month period, 16 house-staff physicians correctly diagnosed 78 +/- 4% of unknown cases presented through the testing module. The 3-D heart model was also perceived to be a useful teaching aid for spatial orientation skills. Our findings suggest that interactive multimedia and volume visualization models can be used to supplement traditional prenatal ultrasound training. The system provides a broad exposure to ultrasound anomalies, increases opportunities for postnatal correlation, emphasizes motion video for ultrasound training, encourages development of independent diagnostic ability, and helps physicians understand anatomic orientation. We hypothesize that interactive multimedia-based tutorials provide a better overall training experience for house-staff physicians. However, these supplementary methods will require formal evaluation of effectiveness to better understand their potential educational impact.

Right fetal cardiac axis: clinical significance and associated findings.

OBJECTIVE: To ascertain the clinical significance of right fetal cardiac axis. METHODS: Fetal cardiac axis was assessed prospectively in ultrasound examinations of 16,562 fetuses over a 6-year period. RESULTS: Twenty-two fetuses had a right cardiac axis. When classified by ventricular and atrial configuration, six fetuses had mirror-image hearts with situs inversus, 12 had rotation of the heart axis alone, and four had inversion of the ventricles. Fourteen of the 22 had underlying structural cardiac defects, most of which were atrioventricular septal defects, double outlet right ventricles, or common atria. The chromosomes and/or phenotypes of all 22 were normal. All four fetuses with polysplenia and asplenia died. Major extracardiac defects were few (two) but lethal. CONCLUSION: Right cardiac axis in the fetus is associated with a high incidence of structural cardiac defects. In the absence of severe extracardiac defects, polysplenia, or asplenia, neonatal outcome was good.

Benign gestational trophoblastic disease metastatic to pleura: unusual cause of hemothorax.

A unique case of hemothorax caused by proven pleural involvement with benign gestational trophoblastic disease and anticoagulation is presented. The pulmonary manifestations of gestational trophoblastic disease are reviewed. It is stressed that these may be associated with histologically benign as well as frankly malignant disease, and that the clinician must be alert for them in managing all patients with known or suspected gestational trophoblastic disease.

Tetralogy of Fallot: prenatal diagnosis and postnatal survival.

OBJECTIVES: To correlate prenatal echocardiographic findings with infant outcome in a large screening population affected by tetralogy of Fallot. METHODS: Inclusion criteria required confirmed postnatal cardiac diagnosis, at least one fetal ultrasound examination with satisfactory heart visualization, and infant delivery at our institution. Aortic and pulmonary artery diameters were measured from real-time ultrasound or videotaped scans and compared against published nomograms. The pulmonary artery to aorta ratio was also evaluated in a similar manner. Infant survival was assessed 1 year after delivery. RESULTS: Seventeen fetuses were confirmed to have a ventricular septal defect and an overriding aorta with varying degrees of right ventricular outflow obstruction after delivery. All karyotypes were normal. Ultrasound screening identified 12 of 17 abnormal hearts at a mean gestational age of 22.9 +/- 5.1 weeks; two of these fetuses were thought to have only ventricular septal defect before delivery. Five fetuses had enlarged aortic roots during the initial scan. Only two of the ten fetuses with a measurable pulmonary artery had initial sonographic evidence for valve stenosis. Six other pulmonary arteries became abnormally small with advancing pregnancy. The pulmonary artery to aorta ratio was decreased in six of the ten fetuses with a measurable pulmonary artery. Sixteen infants survived at least 1 year after birth and successfully completed either corrective or palliative cardiac surgery. CONCLUSION: Fetuses with tetralogy of Fallot may present with only a ventricular septal defect and aortic septal override by prenatal ultrasound examination. Pulmonary artery stenosis is not always present at initial ultrasound examination, but this finding can develop or worsen during pregnancy. Furthermore, a normal aortic diameter does not exclude tetralogy of Fallot. Infant survival appears to be favorable in the absence of other major structural or chromosomal anomalies.

Prenatal screening for cardiac anomalies: the value of routine addition of the aortic root to the four-chamber view.

OBJECTIVE: To determine whether the addition of the aortic-root view would detect more congenital cardiac anomalies than a standard four-chamber view alone. METHODS: The study included fetuses of 14 weeks' gestation or more who were scanned in our unit during a 28-month period. Outcome information was obtained from postnatal echocardiograms and autopsies. Abnormal hearts were classified as to whether the four-chamber or aortic-root view was abnormal. RESULTS: There were 5967 fetuses in whom a four-chamber view could be obtained. In 5111 of these, an aortic-root view could also be obtained. The four-chamber view detected 24 (47%) of the 51 fetuses with abnormal hearts. Adding the aortic-root view increased the sensitivity to 78%. CONCLUSIONS: Visualization of the aortic root is a quick and easy means of evaluating the aortic outflow tract during routine scanning. Adding the aortic-root view to the standard four-chamber view will result in the detection of most cardiac anomalies prenatally.

Maternal diabetes mellitus: which views are essential for fetal echocardiography?

OBJECTIVE: To determine which fetal echocardiography views are essential to detect the majority of cardiac defects in fetuses of women with diabetes mellitus. METHODS: Fetal echocardiograms performed from February 1990 through May 1996 on insulin-requiring women with diabetes were reviewed. Individual component views of the examination were analyzed for the detection of fetal congenital heart defects. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated. Multiple gestations and patients with additional risk factors for congenital heart defects were excluded. RESULTS: A total of 223 patients were included in the study. There were 11 (4.9%) congenital heart defects, eight of which were conotruncal. When the four-chamber view and outflow tracts appeared normal, additional views such as the ductal and aortic arches did not detect a cardiac defect. The sensitivity of the four-chamber view for detecting an abnormal heart increased from 73% to 82% with the addition of the aortic outflow tract. There were two false-negative and no false-positive diagnoses. CONCLUSION: The four-chamber and outflow tracts are the essential views that will detect most cardiac defects in fetuses of women with insulin-requiring diabetes mellitus.

Fetal cardiac asymmetry: a marker for congenital heart disease.

OBJECTIVE: To determine the sensitivity of prenatally detected fetal cardiac asymmetry as a sonographic marker for congenital heart disease. METHODS: The normal ratios of pulmonary artery to aorta diameters and of right ventricle to left ventricle diameters were derived from normal fetuses scanned at 17 weeks or more in a 65-month period. Cross-sectional diameters of cardiac ventricles and great arteries were measured at the level of the valves at the time of the scan. Fetuses with confirmed cardiac anomalies detected prenatally during the study were examined to identify how many had cardiac asymmetry, determined by abnormal ratios. RESULTS: Linear regression analysis of the group of 881 normal fetuses showed the normal pulmonary artery to aorta diameter ratio remained constant throughout pregnancy and the normal right ventricle to left ventricle ratio increased slightly with progressing gestational age. The 90% confidence intervals were 0.79, 1.24 for the right ventricle to left ventricle ratio and 0.84, 1.41 for the pulmonary artery to aorta ratio. Of the 73 fetuses with abnormal hearts, 66% had either ventricular or great artery asymmetry (at least one of the two ratios was abnormal). However, if no asymmetry was present, the cardiac defect was more likely to be a minor one. CONCLUSION: Cardiac asymmetry was present in two-thirds of fetuses with cardiac anomalies diagnosed prenatally. If cardiac asymmetry is found, a more thorough examination of the fetal heart is indicated.

Sonographic screening to detect fetal cardiac anomalies: a 5-year experience with 111 abnormal cases.

OBJECTIVE: To determine whether there is a difference between the types of cardiac lesions detected as abnormal prenatally and those that are not detected. METHODS: Consecutive fetuses at 14 weeks' gestation or more were scanned in our unit from February 1990 through July 1995 and later were delivered at our hospital. Outcome information was obtained from neonatal echocardiograms and autopsies. Our results were compared to sensitivities for individual cardiac lesions based on pooled data from studies published previously. RESULTS: There were 111 fetuses with cardiac anomalies, of which 73 (66%) were identified correctly as abnormal prenatally. Sensitivities for the most common cardiac lesions were as follows: 87% atrioventricular septal (endocardial cushion) defects, 65% tetralogy of Fallot, 63% transposition of the great arteries, 50% aortic coarctation, and 44% isolated ventricular septal defects. The lesions that went undetected most frequently were isolated septal defects (n = 17); most of these were ventricular and small or moderate in size. Based on our sensitivities and those calculated from previous studies, the fetal cardiac lesions with the highest detection rates involve hypoplastic ventricles and atrioventricular septal defects, followed by lesions of the great arteries and finally by isolated septal defects. CONCLUSIONS: The sensitivity of sonographic screening to defect fetal cardiac anomalies varies with the type of lesion. Isolated septal defects are the most difficult lesions to detect.