Structural and functional cardiac abnormalities identified prior to 16 weeks' gestation in fetuses with increased nuchal translucency

Heterotaxy Syndrome with Increased Nuchal Translucency and Normal Karyotype Associated with Complex Systemic Venous Return. Ultrasound Diagnosis with Autopsy Correlation

Background: Prenatal ultrasound (US) detection of heterotaxy syndrome can be challenging, especially in identifying cardiovascular and associated anomalies. We present a new case of heterotaxy syndrome with anomalous systemic venous return (ASVR) fully displayed at autopsy. Case report: Left heterotaxy syndrome was diagnosed in a 19 weeks' of gestation fetus with right-sided stomach. The heart showed both ventricles with left morphology, a large ventricular septal defect, persistent left superior vena cava draining into the coronary sinus, ASVR with interrupted inferior vena cava (IVC) and azygous continuation. Autopsy dissection further identified the azygous draining into the left lower pulmonary vein (LLPV). Prenatal a-CGH on villous sampling showed 22q13.1 microduplication inherited from the father, not contributory to the phenotype. Conclusion/discussion: Heterotaxy syndrome requires US accuracy for anomaly identification, as they allow legal termination of pregnancy. Our case is unusual as IVC drained into the azygous vein and then into the LLPV.

Prenatal and postnatal echocardiography in NT fetuses with normal karyotype

INTRODUCTION

Targeted fetus echocardiography at midpregnancy can detect major defects in major cardiovascular organs. The present study aimed to evaluate prenatal and postnatal echocardiography in fetuses with increased nuchal translucency (NT) with normal karyotype.

METHODS

In this retrospective study, data on the screening of fetuses in pregnant women between 2014 and 2015 were evaluated. The fetuses at the gestational age were 14-11 weeks, and NT ≥ 95 percentile (or 3 mm). For all fetuses with increased NT, follow-up anomaly scan was performed at 18-22 weeks of pregnancy, while fetal echocardiography was performed at weeks 16-19 of pregnancy. The results were analyzed by Statistical Package for the Social Sciences (version 22) and the level of significance was less than 0.05.

RESULTS

A total of 26.27% of the fetuses were diagnosed with prenatal heart defects and confirmed after birth. The strongest relationship was observed between increased NT and the diagnosis of prenatal heart defects at 2.5-5.3 mm. The increased NT was higher in younger mothers. Moreover, increased NT was higher in mothers with less body mass index.

CONCLUSION

By measuring NT in the 11-13 weeks of pregnancy and considering the risk factors, it is possible to evaluate the probability of cardiac abnormalities in the fetus and perform the necessary diagnostic evaluations for high-risk cases.

Intrauterine death in singleton pregnancies with trisomy 21, 18, 13 and monosomy X

Summary A retrospective study from November 2004 to May 2012, conducted at the Obstetric Clinic of Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (HC-FMUSP), which included 92 singleton pregnancies with prenatal diagnosis of trisomy of chromosome 21 (T21), 18, 13 (T13/18) and monosomy X (45X), with diagnosis performed until the 26th week of pregnancy. The aim of the study was to describe the frequency and to investigate predictors of spontaneous fetal death (FD). Diagnosis (T21, n=36; T13/18, n=25; 45X, n=31) was made at a mean gestational age of 18.3±3.7 weeks, through chorionic villus biopsy (n=22,24%), amniocentesis (n=66, 72%) and cordocentesis (n=4, 4%). Major malformations were present in 45 (49%); with hydrops in 32 (35%) fetuses, more frequently in 45X [n=24/31, 77% vs. T21 (n=6/36, 17%) and T13/18 (n=2/25, 8%), p<0.001]. Specialized fetal echocardiography was performed in 60% (55/92). Of these, 60% (33/55) showed changes in heart morphology and/or function. Fetuses with T13/18 had a higher incidence of cardiac anomalies [60 vs. 25% (T21) and 29% (45X), p= 0.01]. FD occurred in 55 (60%) gestations, being more frequent in 45X [n=26/31, 84% vs. T21 (n=13/36, 36%) and T13/18 (n=16/25, 64%), p<0.01]. Stepwise analysis showed a correlation between hydrops and death in fetuses with T21 (LR= 4.29; 95CI=1.9-8.0, p<0.0001). In fetuses with 45X, the presence of echocardiographic abnormalities was associated with lower risk of FD (LR= 0.56; 95CI=0.27- 0.85, p=0.005). No predictive factors were identified in the T13/18 group. Intra- uterine lethality of aneuploid fetuses is high. Occurrence of hydrops increases risk of FD in pregnancies with T21. In pregnancies with 45X, the occurrence of echocardiographic changes reduces this risk.

Collaborative study of 4-dimensional fetal echocardiography in the first trimester of pregnancy

OBJECTIVES

Accumulating evidence supports a role for 2-dimensional fetal echocardiography in the first trimester of pregnancy for the identification of congenital heart defects. Our objective was to investigate the role of 4-dimensional (4D) sonography in the identification of congenital heart defects between 11 and 15 weeks of pregnancy.

METHODS

This study included 4 centers with expertise in first-trimester 4D fetal echocardiography. Fetuses with and without confirmed heart defects were evaluated between 11 and 15 weeks and their volume data sets were uploaded onto a centralized file transfer protocol server.

RESULTS

Forty-eight volume data sets from fetuses with normal (n = 17) and abnormal (n = 16) hearts were evaluated. Overall, the median (range) accuracy, sensitivity, and specificity, as well as the positive and negative likelihood ratios, for the identification of fetuses with congenital heart defects were 79% (77%-83%), 90% (70%-96%), 59% (58%-93%), 2.35 (2.05-9.80), and 0.18 (0.08-0.32), respectively.

CONCLUSIONS

(1) Four-dimensional fetal echocardiography can be performed in the first and early second trimesters of pregnancy; and (2) 4D volume data sets obtained from fetuses between 11 and 15 weeks can be remotely acquired and accurately interpreted by different centers.

Accuracy of ultrasonography at 11-14 weeks of gestation for detection of fetal structural anomalies: a systematic review

OBJECTIVE

To review the literature concerning the efficacy of early ultrasonography (at 11-14 weeks of gestation) to identify fetal malformations.

DATA SOURCES

A search in PubMed, MEDLINE, Embase, Cochrane Library, and ClinicalTrials.gov was performed (January 2000 to December 2012). Keywords were: fetal anatomy, fetal echocardiography, nuchal translucency, fetal structural anomalies, fetal malformations, prenatal diagnosis, prenatal screening, and first-trimester ultrasonography.

METHODS OF STUDY SELECTION

Inclusion criteria were: fetal anatomy examination at early ultrasonography and diagnosis of fetal malformations confirmed by postnatal or postmortem examination. Data abstracted were: sample size, location of structural defect, ultrasound modality, presence of multiple defects, and study population. Pooled detection rate was calculated for each malformation and compared with χ. Differences were considered statistically significant if P<.05.

TABULATION, INTEGRATION, AND RESULTS

From 1,203 articles, 19 were included. Overall, we pooled 78,002 fetuses undergoing ultrasonography at 11-14 weeks, of which 996 were malformed, leading to prevalence of malformation of 12 per 1,000. The overall detection rate was 472 of 957 (51%). The highest detection rate was achieved for neck anomalies (92%), whereas limbs (34%), face (34%), and genitourinary anomalies (34%) were associated with the lowest detection rate. At 14 weeks of gestation or less, fetal echocardiography detected 53% of congenital heart disease compared with 43% by complete scan (P=.040). The use of Doppler did not improve the detection rate for congenital heart defects (52% compared with 44%, respectively; P=.11). Multiple defects were identified more frequently than isolated malformations (60% compared with 44%; P=.005). The detection rate was higher combining transabdominal and transvaginal techniques (62%) than either abdominal (51%) or transvaginal (34%; P<.001). Detection rate was higher in women at high risk (65%) than unselected population (50% P=.001).

CONCLUSION

Because of the natural history of fetal defects and the late development of some organ systems, a number of fetal malformations remain undetected by early ultrasonography.

Twenty-five years of fetal echocardiography in conjoined twins: lessons learned

BACKGROUND

The aim of this study was to determine the accuracy of prenatal echocardiography in the diagnosis of intracardiac malformations and the degree of cardiac fusion in conjoined twins presenting to a single center over a 25-year period.

METHODS

The study group included 53 sets of conjoined twins from 1987 to 2012, including 38 thoracopagus, six parapagus, six omphalo-ischiopagus, two omphalopagus, and one cephalopagus. Twins were classified according to the degree of cardiac fusion: separate hearts and pericardium (group A, n = 10), separated hearts and common pericardium (group B, n = 2), fused atria and separated ventricles (group C, n = 2), and fused atria and ventricles (group D, n = 39). Postmortem examination was possible in 68 individual cases (98 deaths [69.3%]).

RESULTS

Cardiac defects were diagnosed in 47 sets of twins (88.6%). In 10 (18.8%), only one fetus was affected, and in 37 (69.8%), both fetuses were affected (n = 84/106 [79.2%]). There was a high predominance of right-sided lesions (63.0% [53 fetuses in 84 affected]) including pulmonary atresia or stenosis (35.7%), tricuspid atresia (11.9%), and hypoplastic or small right ventricle (21.4%). Autopsy findings added information to fetal echocardiographic findings in nine sets of twins (25.7%). Three pairs classified antenatally in groups A, B, and D were confirmed by autopsy in groups B, C, and C, respectively.

CONCLUSIONS

This study demonstrates that specialized fetal echocardiography is not a perfect diagnostic tool but is sensitive enough to establish prognosis in the counseling process. Because of complexity, such evaluations should be performed only at tertiary centers by specialists who are familiar with the peculiarities of this rare malformation. The predominance of right-sided lesions is not only an interesting finding, but this information has essential importance in terms of shortening examination times, allowing a more focused analysis of the fetal heart.

Echocardiography in Early Pregnancy

Within the last decade, two significant events have contributed to the increasing interest in early fetal echocardiography. First, the introduction of high frequency vaginal ultrasound probes allows detailed visualization of cardiac structures at early stage of gestation, making early detection of fetal malformations possible. Second, the close relationship observed between some first trimester sonographic and Doppler markers and congenital heart defects allows an early identification of a high-risk group at 11 to 14 weeks of gestation. In this context, from the early 1990s, many authors have examined the potential role of the transvaginal approach to obtain earlier diagnosis of fetal cardiac malformations. Further studies have appeared in the literature showing that early transvaginal echocardiography in experienced hand is a fairly sensitive investigative tool. Although some malformations are detected as early as 11 weeks’ gestation, the optimal gestational age to perform the early scan is at least 13 weeks’ gestation. Transvaginal ultrasound is the preferred approach, although most of the authors agree that results can be improved if transabdominal ultrasound is also incorporated. The further application of color Doppler enhances visualization. The sensitivity and specificity of early fetal echocardiography for the detection of heart anomalies is acceptable compared to the ones obtained by mid-gestational echocardiography, showing a slight reduction in detection rates and an increase in false positive and negative rates. The cardiac anomalies detected at this early stage of pregnancy are mainly defects involving the four-chamber view, indicating that defects solely affecting the outflow tracts are difficult to diagnose in the first trimester of pregnancy. Heart defects diagnosed early in pregnancy tend to be more complex than those detected later, with a higher incidence of associated structural malformations, chromosomal abnormalities and spontaneous abortions. The neonate follow-up or postmortem examination in case of termination of pregnancy (TOP) is essential to assess the actual role of early fetal echocardiography. At present, early fetal echocardiography is a promising technique, which can be of considerable value for patients at high-risk. This technique is, however, currently limited to a few specialized centers.

The aim of this review is to explore the possibilities of examining the fetal heart at this early stage of pregnancy. This article also present our experience in the first multicenter trial in early fetal echocardiography performed in Spain. In accordance with other studies, this experience stresses the usefulness of early echocardiography when performed by expert operators on fetus specifically at risk for cardiac defects. Our review of these additional 48 cases contributes to the expanding literature on the ability of transvaginal ultrasonography to detect fetal heart defects in early pregnancy.

How to cite this article

Gabriel CC, Rodriguez PP. Echocardiography in Early Pregnancy. Donald School J Ultrasound Obstet Gynecol 2013;7(2):168-181.

Increased nuchal translucency and congenital heart disease

Sonographic assessment of fetal nuchal translucency (NT) thickness is the cornerstone of screening for chromosomal abnormality at 11-13(+6) weeks gestation. This marker was first recognized in pregnancies being karyotyped for advanced maternal age, but its underlying pathophysiology remains to be fully determined. Although increased NT is clearly associated with changes in both lymphatic and cardiac development, neither is an obvious causative agent. The association with cardiac defects has now being subjected to a significant amount of research, with a large body of evidence showing that this marker is also a screening tool for major cardiac defects - although it performs more modestly than for chromosomal abnormality. The field continues to change rapidly. Recent evidence that uses a combination of increased NT, tricuspid regurgitation and abnormal flow in the 'a' wave of the ductus venosus can provide an effective screening strategy to predict many major cardiac defects at this early stage of pregnancy.

Additional first-trimester ultrasound markers

The first trimester (11-13 +6 weeks) ultrasound examination is useful for several reasons: determination of an accurate date of confinement, diagnostic purposes, and screening for fetal defects. Nuchal translucency measurement combined with maternal serum markers (free b-human chorionic gonadotropin and pregnancy-associated plasma protein A) is the mainstay of first-trimester screening for chromosomal defects. However, over the past decade additional ultrasound markers have been developed that improve the performance of this type of screening. The novel markers include evaluation of the nasal bone, fronto-maxillary angle measurement, and Doppler evaluations of the blood flow across the tricuspid valve and in the ductus venosus.

Increased nuchal translucency in euploid fetuses--what should we be telling the parents?

Nuchal translucency (NT) measurement between 11 and 14 weeks' gestation is an undisputed marker for aneuploidies. When conventional karyotyping is normal, enlarged NT is a strong marker for adverse pregnancy outcome, associated with miscarriage, intrauterine death, congenital heart defects, and numerous other structural defects and genetic syndromes. The risk of adverse outcome is proportional to the degree of NT enlargement. Although the majority of structural anomalies are amenable to ultrasound detection, unspecified genetic syndromes involving developmental delay may only emerge after birth. Concern over these prenatally undetectable conditions is a heavy burden for parents. However, following detection of enlarged NT the majority of babies with normal detailed ultrasound examination and echocardiography will have an uneventful outcome with no increased risk for developmental delay when compared to the general population. Counseling should emphasize this to help parents restore hope in normal pregnancy outcome and infant development.

Nuchal translucency and cystic hygroma colli in screening for fetal major congenital heart defects in a series of 12,910 euploid pregnancies

OBJECTIVE

Many studies have shown that an increased nuchal translucency (NT) may be a good marker of fetal heart malformation, but the extent to which NT is suitable for identifying the population at risk remains unclear. We aimed to determine the value of NT measurement and of the presence of cystic hygroma colli in the screening of euploid fetuses for congenital heart defects (CHD).

METHODS

We carried out a retrospective analysis of 12 910 euploid pregnancies examined between January 1995 and August 2007 at our institution. The screening performance of NT measurements in identifying fetuses with CHD was assessed, with comparison between the use of cut-offs defined as absolute values, multiples of the median (MoM) and percentiles. The presence of cystic hygroma colli was also assessed in the prediction of CHD.

RESULTS

The incidence of major CHD was 3.4 per thousand (44/12 910). The sensitivity of NT measurement in screening for major CHD was 54.5% if the threshold was set at the 95(th) percentile, 45.4% if it was set at 3 mm, 27.3% for 3.5 mm, 50.0% for 1.5 MoM and 45.5% for 1.75 MoM. The false-positive rates for these thresholds were 8.4, 6.6, 1.7, 8.9 and 6.3%, respectively. The incidence of major CHD was 1.2% (10/813) in cases of thick NT (> 95(th) centile) and 4.3% (13/304) in cases of hygroma colli.

CONCLUSIONS

NT measurement during the first trimester is potentially useful for screening for fetal major CHD. Screening performance is consistent whether NT values are expressed as MoMs, percentiles or absolute values. The incidence of major CHD seems to be higher in cases of cystic hygroma colli.

First Trimester Ultrasound Screening: An Update

For many years, the main use of ultrasound in the first trimester of pregnancy was to confirm viability and to establish gestational age. Indeed, the crown-rump length measurement in the first trimester remains the most accurate method to estimate the gestational age even today. However, improvements in ultrasound equipment and improvement in our understanding of normal and abnormal fetal development allows us now to perform a much more complete first trimester fetal evaluation. This pertains not only to the diagnosis of fetal anomalies but also to screening for fetal defects. The combination of the nuchal translucency measurement and maternal serum biochemistries (free β-hCG and PAPP-A) has been shown to be an extremely efficient way to screen for fetal aneuploidy. The addition of other first trimester markers such as the nasal bone evaluation, frontomaxillary facial angle measurement, and Doppler evaluation of blood flow across the tricuspid valve and through the ductus venosus improves the screening performance even further by increasing the detection rates and decreasing the false positive rates. Several of the first trimester markers also are useful in screening for cardiac defects. Furthermore, significant nuchal translucency thickening has been associated with a variety of genetic and nongenetic syndromes. A recently described first trimester marker called the intracerebral translucency appears to hold great promise in screening for open spine defects. Finally, it appears that a first trimester evaluation (uterine artery Doppler and the measurement of certain biochemical markers in the maternal serum) significantly improves the assessment of the risk of preeclampsia.

The nuchal translucency and the fetal heart: a literature review

In this overview the current knowledge of the relationship between an increased nuchal translucency (NT) measurement and fetal heart structure and function in chromosomally normal fetuses is reviewed. Relevant pathophysiological theories behind the increased NT are discussed. Fetuses with an increased NT have an increased risk for congenital heart disease (CHD) with no particular bias for one form of CHD over another. This risk increases with increasing NT measurement. Although the NT measurement is only a modestly effective screening tool for all CHD when used alone, it may indeed be effective in identifying specific CHD "likely to benefit" from prenatal diagnosis. The combination of an increased NT, tricuspid regurgitation and an abnormal ductus venosus (DV) Doppler flow profile, is a strong marker for CHD. A fetal echocardiogram should be performed at 20 weeks' gestation in fetuses with an NT > or = 95th percentile but < 99th percentile. When the NT measurement is > or = 99th percentile, or when tricuspid regurgitation and/or an abnormal DV flow pattern is found along with the increased NT, an earlier echocardiogram is indicated, followed by a repeat scan at around 20 weeks' gestation. The resultant increased demand for early fetal echocardiography and sonographers with this special expertise needs to be planned and provided for.

Feasibility and accuracy of fetal echocardiography using four-dimensional spatiotemporal image correlation technology before 16 weeks' gestation

OBJECTIVES

To evaluate the potential value of early fetal echocardiography (EFE) by means of four-dimensional (4D) spatiotemporal image correlation (STIC) technology for either reassurance of normality or prenatal diagnosis of major congenital heart defects (CHDs).

METHODS

Sixty-nine pregnant women from 11 to 15 weeks' gestation underwent EFE. 4D-STIC volumes were acquired by the transvaginal approach for later review by two different examiners. STIC evaluation was considered complete when the four-chamber view, and the origin and double-crossing of the great arteries were identified correctly. Color Doppler imaging was used to detect either septal shunts or transvalvular regurgitation/aliasing suggesting abnormalities. STIC diagnoses were compared with those of conventional EFE. Reliability was assessed by postnatal examination, or autopsy in cases of termination of pregnancy or perinatal death.

RESULTS

The median gestational age at volume acquisition was 13 + 3 weeks. Eleven (15.9%) cases of CHD were diagnosed. A complete EFE was possible in 64 cases. We were able to provide reassurance of normality in 51 of the 53 confirmed normal hearts, with no false-positive results for major defects, although two minor defects (one ventricular septal defect (VSD) and one persistent left superior vena cava) were falsely suspected. The only false negative was a significant VSD at birth overlooked by both observers. Therefore, the total accuracy of STIC-EFE was 95.3% (61/64), with sensitivity, specificity, and positive and negative predictive values of 90.9%, 96.2%, 83.3% and 98.1%. The accuracy of conventional EFE (98.4%, 63/64) was slightly better than that of STIC, with no false-positive results recorded.

CONCLUSIONS

Offline evaluation of 4D-STIC acquired volumes of the fetal heart in the first and early second trimester of pregnancy is reliable not only for early reassurance of normal cardiac anatomy but also to diagnose most major structural heart defects.

Perinatal Outcome of Fetal Atrioventricular Block

Background— Fetal atrioventricular (AV) block is an uncommon lesion with significant mortality. Because of the rarity of this disorder, the natural course, extensive evaluation of untreated fetuses, and late follow-up remain unclear.

Methods and Results— Of the 116 consecutive cases of fetal AV block studied from 1988 to 2006, only 1 was terminated, and 75% were live births. Fifty-nine cases of AV block were associated with major structural heart disease, mainly left atrial isomerism (n=40), with only 26% of neonatal survivors. Of the 57 fetuses with normal cardiac anatomy, 41 (72%) were positive for maternal antinuclear antibodies, and 32 of these seropositive mothers did not receive any treatment. This untreated group had live-birth and 1-year infant survival rates of 93% and 90%, respectively. Five fetuses from seronegative mothers showed regression to sinus rhythm during pregnancy. The presence of major structural heart disease, hydrops, an atrial rate ≤120 bpm, and a ventricular rate ≤55 bpm were identified as risk factors for mortality. Logistic regression analysis of the whole group showed that the presence of structural heart disease was the only independent predictor of death ( P <0.001).

Conclusions— This long-term study confirms that fetal AV block has a poor outcome when associated with structural heart disease and that spontaneous regression of AV block is possible in seronegative forms. The survival rate of >90% of our untreated patients with isolated forms of AV block raises concerns about any decision to intervene with immunosuppressive agents.

Implications of bidirectional flow in the great arteries at the 11-14-week scan

OBJECTIVE

To determine the implications of a bidirectional Doppler flow pattern detected in one or both of the fetal great arteries in the first trimester.

METHODS

Database records were reviewed for cases of bidirectional flow found on fetal echocardiography performed at less than 15 weeks of gestation between January 1999 and October 2006 inclusive. Bidirectional flow consisted of antegrade flow in systole and retrograde flow in diastole. Data including indication for fetal echocardiography, gestational age at diagnosis, the anatomical features, karyotype, nuchal translucency measurement and outcome were collected.

RESULTS

From almost 2500 scans, bidirectional flow was detected in a total of 15 fetuses. The abnormal flow pattern was confined to the aorta in four, to the pulmonary artery in four, and was present in both great arteries in a further seven fetuses. Eight of the 15 fetuses had regurgitation at one or both atrioventricular valves. Additional cardiac abnormalities were detected by ultrasound in eight cases. Of the 13 cases for which the karyotype was known, 12 were abnormal and five of these had trisomy 18. None of the fetuses survived. There were two intrauterine deaths and 13 terminations of pregnancy.

CONCLUSION

Bidirectional flow in one or both great arteries is an unusual finding at the first-trimester scan and must be distinguished from the retrograde flow occurring only in systole in duct-dependent heart defects. It carries a poor prognosis, which is a consequence of both the high chance of underlying chromosomal abnormality and the hemodynamic compromise associated with severe arterial valve regurgitation.

First trimester ultrasonography in screening and detection of fetal anomalies

An obstetrical ultrasound examination provides invaluable information regarding the fetus. Until the mid-1980s, ultrasound in the first trimester was limited to localization of the pregnancy, establishing viability, and accurate dating. With the advent of high-resolution ultrasound and transvaginal scanning, a significant amount of information about the fetus can be gained and provided to the patient at a very early stage in gestation. This article provides an overview of the role of first trimester (11-13 + 6 weeks' gestation) ultrasound in screening and diagnosis of fetal anomalies. The first trimester is an ideal time for screening for aneuploidy, primarily due to the advantages that nuchal translucency (NT) measurement provides. NT measurement is also useful in establishing the risk of congenital cardiac disorders and a number of genetic and non-genetic syndromes. Significant NT thickening is associated with an increase in perinatal morbidity and mortality. Potential mechanisms resulting in increased NT are discussed. A number of new ultrasound markers for fetal aneuploidy have been investigated over the past several years, some of which appear to improve the screening efficacy of early ultrasonography. The role of these is reviewed. A number of fetal anomalies can now be consistently diagnosed in the first trimester. Their appearance at this early gestational age is discussed as well. It is clear that, data obtained by first trimester ultrasound are useful in counseling expectant parents and in planning the appropriate follow-up.

First and early second trimester fetal heart screening

PURPOSE OF REVIEW

This review describes the recent advances in timing and effectiveness of first and early second trimester fetal echocardiography screening.

RECENT FINDINGS

Fetal echocardiography can now be reliably performed from 11 weeks' gestation owing to improvements in ultrasound transducers and processors. Three-dimensional and four-dimensional ultrasound modalities in image acquisition and postprocessing analysis, including spatio-temporal image correlation, rendering three-dimensional power Doppler and high definition power flow Doppler, and B-flow have further improved our capabilities in this area. Fetal nuchal translucency measurement screening programs create a new population of at-risk pregnancies that will be referred for early fetal echocardiography. The majority of congenital heart defects, however, still occur in low-risk patients. Improved technology has lowered the gestational age at which fetal cardiac anatomy scanning can be reliably performed by properly trained and experienced examiners.

SUMMARY

Early fetal echocardiography can be offered as a screening examination to at-risk and low-risk patients, with the proviso that it be repeated following screen-negative scans at mid-gestation to exclude later developing lesions.

My approach to performing a perinatal or neonatal autopsy

An opportunity to determine the cause of death, factors that may have a role in it, and the extent and cause of malformations is provided by perinatal autopsy. The family may be assisted in finding closure after the death of their infant by the information obtained. Insight into classifying infants appearing normal into one of three groups, small, appropriate and large for gestational age, has been provided, as each group tends to have specific causes of death. In infants with congenital anomalies, patterns of malformation may lead us to the diagnosis. An accurate diagnosis is required to provide counselling for a subsequent pregnancy.

Detailed screening for fetal anomalies and cardiac defects at the 11-13-week scan

OBJECTIVE

To assess the diagnostic efficacy of the first-trimester anomaly scan including first-trimester fetal echocardiography as a screening procedure in a 'medium-risk' population.

METHODS

In a prospective study, we evaluated 3094 consecutive fetuses with a crown-rump length (CRL) of 45-84 mm and gestational age between 11 + 0 and 13 + 6 weeks, using transabdominal and transvaginal ultrasonography. The majority of patients were referred without prior abnormal scan or increased nuchal translucency (NT) thickness, the median maternal age was, however, 35 (range, 15-46) years, and 53.8% of the mothers (1580/2936) were 35 years or older. This was therefore a self-selected population reflecting an increased percentage of older mothers opting for prenatal diagnosis. The follow-up rate was 92.7% (3117/3363).

RESULTS

The prevalence of major abnormalities in 3094 fetuses was 2.8% (86/3094). The detection rate of major anomalies at the 11 + 0 to 13 + 6-week scan was 83.7% (72/86), 51.9% (14/27) for NT < 2.5 mm and 98.3% (58/59) for NT >or= 2.5 mm. The prevalence of major congenital heart defects (CHD) was 1.2% (38/3094). The detection rate of major CHD at the 11 to 13 + 6-week scan was 84.2% (32/38), 37.5% (3/8) for NT < 2.5 mm and 96.7% (29/30) for NT >or= 2.5 mm.

CONCLUSION

The overall detection rate of fetal anomalies including fetal cardiac defects following a specialist scan at 11 + 0 to 13 + 6 weeks' gestation is about 84% and is increased when NT >or= 2.5 mm. This extends the possibilities of a first-trimester scan beyond risk assessment for fetal chromosomal defects. In experienced hands with adequate equipment, the majority of severe malformations as well as major CHD may be detected at the end of the first trimester, which offers parents the option of deciding early in pregnancy how to deal with fetuses affected by genetic or structural abnormalities without pressure of time.

Ras-related signaling pathways in valve development: ebb and flow

Congenital heart defects affect approximately 1 in every 100 live births, and deficits in the formation of the mitral, tricuspid, and outflow tract valves account for 20-25% of all cardiac malformations. Mutations in genes that affect Ras signaling have been identified in individuals with congenital valve disease associated with Noonan syndrome and neurofibromatosis type 1. Dissection of Ras-related signaling pathways during valvulogenesis provides seminal insight into cellular and molecular mechanisms that contribute to congenital heart disease.

Three- and 4-dimensional ultrasound in obstetric practice: does it help?

OBJECTIVE

The purpose of this article was to review the published literature on 3-dimensional ultrasound (3DUS) and 4-dimensional ultrasound (4DUS) in obstetrics and determine whether 3DUS adds diagnostic information to what is currently provided by 2-dimensional ultrasound (2DUS) and, if so, in what areas.

METHODS

A PubMed search was conducted for articles reporting on the use of 3DUS or 4DUS in obstetrics. Seven-hundred six articles were identified, and among those, 525 were actually related to the subject of this review. Articles describing technical developments, clinical studies, reviews, editorials, and studies on fetal behavior or maternal-fetal bonding were reviewed.

RESULTS

Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, especially facial clefts. There is also evidence that 3DUS provides additional diagnostic information in neural tube defects and skeletal malformations. Large studies comparing 2DUS and 3DUS for the diagnosis of congenital anomalies have not provided conclusive results. Preliminary evidence suggests that sonographic tomography may decrease the examination time of the obstetric ultrasound examination, with minimal impact on the visualization rates of anatomic structures.

CONCLUSIONS

Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, evaluation of neural tube defects, and skeletal malformations. Additional research is needed to determine the clinical role of 3DUS and 4DUS for the diagnosis of congenital heart disease and central nervous system anomalies. Future studies should determine whether the information contained in the volume data set, by itself, is sufficient to evaluate fetal biometric measurements and diagnose congenital anomalies.

Increased nuchal translucency with normal karyotype

Increased fetal nuchal translucency (NT) thickness between 11 and 14 weeks' gestation is a common phenotypic expression of chromosomal abnormalities, including trisomy 21. However, even in the absence of aneuploidy, nuchal thickening is clinically relevant because it is associated with an increase in adverse perinatal outcome caused by a variety of fetal malformations, dysplasias, deformations, dysruptions, and genetic syndromes. Once the presence of aneuploidy is ruled out, the risk of perinatal outcome dose not statistically increase until the nuchal translucency measurement reaches 3.5 mm or more (>99th percentile). This increase in risk occurs in an exponential fashion as the NT measurement increases. However, if the fetus survives until midgestation, and if a targeted ultrasound at 20 to 22 weeks fails to reveal any abnormalities, the risk of an adverse perinatal outcome and postnatal developmental delay is not statistically increased.

Does nuchal translucency have a role in fetal cardiac screening?

Increased nuchal translucency is the strongest single marker for chromosomal abnormality. Consequently, it is currently becoming established as the foundation of most early screening programmes for Down syndrome. In the absence of chromosomal abnormality, increased nuchal translucency has been shown to be associated with other congenital anomalies including cardiac defects. Several datasets have now reported this association and here these are reviewed to assess the effectiveness of nuchal translucency measurement as a screening tool for the prenatal detection of congenital heart disease.