Increased nuchal translucency at 10-14 weeks of gestation as a marker for major cardiac defects

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.

[First trimester fetal cardiac scanning for fetuses at higher risk for congenital heart disease]

OBJECTIVE

To describe the preliminary results of fetal cardiac scanning in the first trimester of pregnancy for fetuses at higher risk for congenital heart defect (CHD).

PATIENTS AND METHODS

Echocardiographic examination was performed at 12 to 14+6 in 67 patients at higher risk for fetal CHD. The indications for referral were: increased nuchal translucency more or equal to 99(e) centile (56 cases), risk of recurrence for CHD (eight cases), embryonic toxic exposure (eight cases), maternal disease (four cases).

RESULTS

Complete examination of the fetal heart was possible in 54/55 cases. Fetal cardiac examination was normal in 58 cases (87 %). Six cases of severe CHD were diagnosed: hypoplastic left heart syndrome, pulmonary atresia with intact septum, complex univentricular CHD leading to termination of pregnancy, conotroncal Fallot like abnormality, and transposition of great arteries. Post-mortem examination was performed in three cases and confirmed the cardiac anomalies.

DISCUSSION AND CONCLUSION

Our preliminary results confirmed that fetal heart scanning is feasible at the end of the first trimester of pregnancy. Severe CHD are amenable to prenatal diagnosis in the first trimester in the population at higher risk for CHD.

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.

Fetal thickened nuchal soft tissues may first appear in the second trimester in Down syndrome

PURPOSE

To describe a series of cases of late-onset fetal nuchal translucency in Down syndrome.

METHOD

In our practice area, most pregnant women usually undergo 3 different sonographic examinations: a fetal nuchal translucency examination in the 1st trimester and 2 detailed surveys of all fetal organs in the early 2nd trimester and in midpregnancy.

RESULT

During the study period (2003-2008), we detected 11 fetuses with new appearance of severe thickened nuchal soft tissues (>or=6 mm) at 14-16 weeks' gestation after a normal nuchal screening in the 1st trimester. All of these fetuses had trisomy 21. Associated structural anomalies were observed in 10/11 of the cases. In addition, there were 12 fetuses with new appearance of thickened nuchal soft tissues (<4 mm); all these fetuses had a normal karyotype and were normal at delivery.

CONCLUSION

Obstetricians should be aware that a nuchal abnormality may first appear only at 14-16 weeks' gestation. Fetal karyotyping is advocated in these cases because of the high probability of Down syndrome.

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.

Abnormal Shh and FOXC2 expression correlates with aberrant lymphatic development in human fetuses with increased nuchal translucency

OBJECTIVE

Previous research in fetuses with increased nuchal translucency (NT) showed abnormal lymphatic endothelial differentiation characteristics, including increased vascular endothelial growth factor (VEGF)-A expression, and aberrant smooth muscle cells (SMCs) surrounding enlarged jugular lymphatic sacs (JLS). We hypothesized that abnormal Sonic hedgehog (Shh) expression would result in altered VEGF-A signaling in the lymphatic endothelial cells of the JLS and that aberrant acquisition of SMCs could be caused by downregulation of forkhead transcription factor FOXC2 and upregulation of platelet-derived growth factor (PDGF)-B in the lymphatic endothelial cells of the JLS.

METHODS

Five trisomy 21 fetuses and four controls were investigated using immunohistochemistry for Shh, VEGF-A, FOXC2 and PDGF-B expression in the lymphatic endothelial cells of the JLS.

RESULTS

An increased Shh, VEGF-A and PDGF-B expression, and decreased FOXC2 expression were shown in the lymphatic endothelial cells of the JLS of the trisomic fetuses.

CONCLUSIONS

Increased Shh and VEGF-A expression is correlated with an aberrant lymphatic endothelial differentiation in trisomy 21 fetuses. The SMCs surrounding the JLS can possibly be explained by an increase of PDGF-B-induced SMC recruitment and/or differentiation. This underscores earlier findings that indicate the loss of lymphatic identity in trisomy 21 fetuses and a shift towards a blood vessel wall phenotype.

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.

Prenatal diagnosis of congenital heart disease

This article presents advancements in the field of fetal echocardiography and the significant impact of these within the fields of pediatric cardiology, perinatology, and neonatology. A prenatal diagnosis of congenital heart disease allows for improved counseling of the parents, guides the timing and optimal location of delivery, and allows appropriate planning and consultation between the cardiologist and neonatologist. It also facilitates accurate diagnosis and management of fetal arrhythmias, identifies potential candidates for in utero cardiac intervention, and serves as the imaging guidance technique for these procedures. The goals, indications, advantages, limitations, and spectrum of congenital heart disease that can be diagnosed are reviewed.

Ductus venosus Doppler in fetuses with cardiac defects and increased nuchal translucency thickness

OBJECTIVE

To examine the possible role of Doppler ultrasound assessment of ductus venosus blood flow in screening for major cardiac defects in chromosomally normal fetuses with increased nuchal translucency (NT) thickness at 11 + 0 to 13 + 6 weeks' gestation.

METHODS

Ductus venosus blood flow velocity waveforms were obtained immediately before chorionic villus sampling for fetal karyotyping in fetuses with NT thickness of 3.5 mm or more at 11 + 0 to 13 + 6 weeks of gestation. In the chromosomally normal group fetal echocardiography was performed by a specialist pediatric cardiologist at 11 + 0 to 13 + 6 weeks and/or 18-22 weeks' gestation.

RESULTS

Major cardiac defects were diagnosed in 16 (8.4%) of the 191 chromosomally normal fetuses. Reversed or absent flow in the ductus venosus during atrial contraction was observed in 11 of the 16 (68.8%) fetuses with cardiac defects and in 40 of the 175 (22.9%) with no cardiac defects. Multivariate analysis demonstrated that the prevalence of an abnormal A-wave in the ductus venosus in fetuses without major cardiac defects increased with fetal NT thickness (odds ratio (OR), 1.463; 95% CI, 1.183-1.809; P < 0.0001) but in those with cardiac defects it did not change significantly with NT thickness (OR, 2.054; 95% CI, 0.573-7.360; P = 0.269). The likelihood ratio for a major cardiac defect when the ductus venosus flow was abnormal decreased with fetal NT thickness from 4.58 at NT 3.5 mm to 2.47 for NT 5.5 mm, and the likelihood ratio when the ductus venosus flow was normal increased from 0.37 at NT 3.5 mm to 0.43 for NT 5.5 mm.

CONCLUSION

In chromosomally normal fetuses with increased NT the finding of an absent or reversed A-wave in the ductus venosus is associated with a three-fold increase in the likelihood of a major cardiac defect, whereas the finding of normal ductal flow is associated with a halving in risk for such defects.

Nuchal Translucency and First Trimester Risk Assessment

First-trimester risk assessment for fetal aneuploidy using nuchal translucency (NT) measurement is rapidly gaining popularity in the United States. In combination with maternal serum markers in the first trimester, the screening performance is exceptionally good, with detection rates of more than 80% at a screen positive rate of 5%. Recently, the method has been validated for screening for Down syndrome and other aneuploidies in multicenter trials in the United States and elsewhere. Compliance with established criteria for measurement of the NT is essential to achieve uniform reliability and high screening test sensitivity. There is an international consensus about the importance of specific training in the NT examination, conformity to standards of NT measurement, and regular audit for quality assurance. In the United States, the Nuchal Translucency Quality Review program has been developed to administer credentialing and quality review for registered practitioners. The Nuchal Translucency Quality Review credentials signify the proficiency of the sonographer or sonologist in NT measurement and participation in a regular quality assurance audit. We encourage accreditation of clinical sites offering first-trimester risk assessment to ensure the highest quality care.

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.

Detection of chromosomal abnormalities, congenital abnormalities and transfusion syndrome in twins

OBJECTIVE

To evaluate the outcome of screening for structural malformations in twins and the outcome of screening for twin-twin transfusion syndrome (TTTS) among monochorionic twins through a number of ultrasound scans from 12 weeks' gestation.

METHODS

Enrolled into this prospective multicenter observational study were women with twin pregnancies diagnosed before 14 + 6 gestational weeks. The monochorionic pregnancies were scanned every second week until 23 weeks in order to rule out early TTTS. All pregnancies had an anomaly scan in week 19 and fetal echocardiography in week 21 that was performed by specialists in fetal echocardiography. Zygosity was determined by DNA analysis in all twin pairs with the same sex.

RESULTS

Among the 495 pregnancies the prenatal detection rate for severe structural abnormalities including chromosomal aneuploidies was 83% by the combination of a first-trimester nuchal translucency scan and the anomaly scan in week 19. The incidence of severe structural abnormalities was 2.6% and two-thirds of these anomalies were cardiac. There was no significant difference between the incidence in monozygotic and dizygotic twins, nor between twins conceived naturally or those conceived by assisted reproduction. The incidence of TTTS was 23% from 12 weeks until delivery, and all those monochorionic twin pregnancies that miscarried had signs of TTTS.

CONCLUSION

Twin pregnancies have an increased risk of congenital malformations and one out of four monochorionic pregnancies develops TTTS. Ultrasound screening to assess chorionicity and follow-up of monochorionic pregnancies to detect signs of TTTS, as well as malformation screening, are therefore essential in the antenatal care of twin pregnancies.

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.

Fetal echocardiography at the time of the nuchal translucency scan

OBJECTIVE

The fetal heart is not studied routinely in the first trimester because of technical and time limitations. Our aim was to assess the feasibility of performing a fetal cardiac study in pregnancies referred for nuchal translucency (NT) screening, using high-frequency linear transabdominal transducers with a specific ultrasound preset.

METHODS

A single trained operator assessed the fetal heart in pregnancies with a fetal crown-rump length (CRL) of 60-84 mm that had been referred for NT screening. A 15- or 6-MHz transabdominal linear transducer with a specific preset suitable mainly for color-flow mapping was used to confirm or refute normal cardiac anatomy rather than to establish a specific diagnosis. Fetuses having an increased risk for congenital heart disease were referred to a tertiary center for a further examination within 1 week. This group consisted of all fetuses with NT > 95(th) centile and those in which a family history or the initial heart scan increased the risk.

RESULTS

A total of 608 fetuses with a median CRL of 65 mm was examined between 2003 and 2005. A cardiac scan was performed successfully in 456 (75%) using a 15-MHz linear transducer alone, and the additional use of a 6-MHz transducer allowed diagnostic images to be obtained in a further 152. Normal cardiac anatomy was assessed confidently within 10 min in 517/608 (85%) pregnancies; in 85 (14%) a longer time was needed and six patients were rescheduled within 2 weeks because of non-diagnostic images at the initial scan. In 571/608 (94%) the risk for congenital heart disease (CHD) was not increased and the heart was considered normal at initial echocardiography; this was confirmed by later scans and at postnatal follow-up. In 37/608 (6%) fetuses the risk for CHD was increased (35 for NT > 95(th) centile and two for family history). In this group normal heart anatomy was described in 34 fetuses and confirmed by subsequent specialist echocardiography. Cardiac defects were suspected in three fetuses (all with increased NT) and confirmed by a fetal cardiologist in each case.

CONCLUSIONS

A trained operator can perform a fetal heart study during the NT screening test using transabdominal high-resolution transducers in an acceptable length of time.

Single large study or meta-analysis parameters: choosing the most appropriate tool for Down syndrome screening in the first trimester

AIM

The aim of the present study is to determine whether the use of population parameters derived from meta-analysis produces better test characteristics in the first-trimester combined screening than those obtained from large single studies, when screening for Down syndrome (DS) in singleton pregnancies.

METHODS

Retrospective analysis was done on a database of 4248 singleton pregnancies, including 13 cases of DS, for which the values of three markers used in the combined first-trimester test were available. The risk of DS was calculated for each mother from the different population parameters derived by meta-analysis or from two large single studies: the Fetal Medicine Foundation study (FMF) and the Serum, Urine and Ultrasound Screening Study (SURUSS).

RESULTS

When the detection rate was fixed at about 85%, the false-positive rate was significantly higher (Chi-square = 53.49, p < 0.0001) when the parameters obtained by the meta-analysis (6.25%) were compared with the two single studies (FMF, 4.15% and SURUSS, 3.75%).

CONCLUSIONS

This study highlights the importance of selecting appropriate population parameters when insufficient DS cases are available in the study population. When screening for DS in singleton pregnancies during the first trimester, the use of population parameters derived from single large studies produced better test characteristics.

First-trimester screening

Screening for fetal chromosome abnormalities, particularly for trisomy 21, has made dramatic advances. Better screening demonstrates that "high-risk" patients--particularly over age 35--can have lower risk of defects than younger unscreened women. This has caused reduction of amniocentesis for older patients and made screening available for younger patients who have the universal 2% to 3% risk. This means lower procedural-related losses of normal fetuses, and better resource allocation. The trend toward first-trimester detection of structural defects continues; a normal survey is reassuring and helps exclude major defects. Based on screening results, patients can be triaged into early follow-up and possible amniocentesis as 14 to 16 weeks, or a later detailed anatomic survey at 18 to 20 weeks.

By how much does increased nuchal translucency increase the risk of adverse pregnancy outcome in chromosomally normal fetuses? A study of 16,260 fetuses derived from an unselected pregnant population

OBJECTIVE

In this study we aimed to estimate the magnitude of a possible increase in risk of adverse outcome in fetuses with normal karyotype and increased nuchal translucency (NT), and to determine how well NT measurements can distinguish between fetuses with normal and adverse outcome.

METHODS

We studied 16,260 consecutive fetuses with normal karyotype derived from an unselected pregnant population. The following cut-offs for increased risk of adverse outcome were chosen a priori: NT > or = 95th percentile, > or = 3 mm, > or = 3.5 mm, and > or = 4.5 mm. The positive and negative likelihood ratios (+LR, - LR) of the risk cut-offs with regard to fetal malformation, miscarriage, perinatal death, termination of pregnancy and total adverse outcome were calculated, and receiver-operating characteristics (ROC) curves were drawn.

RESULTS

The total rate of adverse outcome was 2.7%. + LR and - LR of NT > or = 3.0 mm were: for lethal or severe malformation, + LR 15.0 (95% CI 7.0-28.6), - LR 0.89 (95% CI 0.81-0.95); for malformation of at least intermediate severity, + LR 8.1 (95% CI 4.3-14.0), - LR 0.95 (95% CI 0.92-0.97); for termination of pregnancy, + LR 41.6 (95% CI 17.1-86.6), - LR 0.67 (95% CI 0.41-0.85); for any adverse outcome, + LR 6.4 (95% CI 3.4-11), - LR 0.96 (95% CI 0.94-0.98). The odds for these adverse outcomes increased with increasing NT. NT > or = 3 mm did not significantly increase the risk of miscarriage or perinatal death. Areas under ROC curves for NT were small, with 95% CI below or only slightly above 0.5.

CONCLUSION

Our likelihood ratios can be used to calculate the individual risk of unfavorable outcome, but NT screening cannot reliably distinguish between normal and adverse outcome in fetuses with normal karyotype.

Ultrasound screening program for chromosomal abnormalities: The first 2000 women

Introduction Screening for chromosomal abnormalities identifies the group of women at higher risk for having a fetus with chromosomal abnormalities and the need for fetal karyotyping. In order to provide high quality screening, strict criteria for certification of operators are introduced, issued by the Fetal Medicine Foundation (FMF), which enables annual external control of results. The aim of this study was to review the results of five-year prenatal screening for chromosomal abnormalities in Novi Sad, Serbia. Material and methods Ultrasound screening at 11-15 weeks gestation was performed, assessing fetal morphology, crowner-rump length and nuchal translucency (NT) according to the FMF guidelines. Risk for chromosomal abnormalities included the initial risk, based on maternal age, gestational age and anamnestic data, and corrected risk, which took into account the initial risk and the value of the nuchal translucency. The corrected risk was issued by the computer program issued by the FMF. Results During the period 1999 - 2004, 4580 pregnant women were scanned. The risk for chromosomal abnormality was calculated using the FMF program in 2245 cases and the outcome was known in 1406 cases. The majority of women were between 25 and 29 years of age (37%), and 12% were older than 35 years. NT was below the median in 43% of cases and above in 57%, 3.7% of cases were above the 95th centile. 89% of women were younger than 35, and the risk was reduced in 97% of cases. There were three false negative cases. In 3% of women from this group the risk was increased, out of which there were five cases of trisomy 21 and two terminations were done due to major anomalies. In the group of women over 35 years, the risk was reduced in 95% of cases and in all of them but two the karyotype was normal. In one of the two cases there was a large omphalocele and the karyotype was trisomy 18, and in the other fetus appeared normal, but after amniocentesis due to maternal anxiety, karyotype was 47, XYY. In 5% of women at higher risk there was one trisomy 21, bilateral multicystic kidneys were found in one case as well as one hydrocephalus. Conclusion Combined screening by maternal age and nuchal translucency is superior to screening by maternal age only - (sensitivity 66% vs 20%, false postive results 3% vs 15%, area under ROC 0.90 vs 0.69).

3D and 4D ultrasound in fetal cardiac scanning: a new look at the fetal heart

Over the last decade we have been witness to a burgeoning literature on three-dimensional (3D) and four-dimensional (4D) ultrasound-based studies of the fetal cardiovascular system. Recent advances in the technology of 3D/4D ultrasound systems allow almost real-time 3D/4D fetal heart scans. It appears that 3D/4D ultrasound in fetal echocardiography may make a significant contribution to interdisciplinary management team consultation, health delivery systems, parental counseling, and professional training. Our aim is to review the state of the art in 3D/4D fetal echocardiography through the literature and index cases of normal and anomalous fetal hearts.

Prenatal detection of heart defects in a non-selected population of 30,149 fetuses--detection rates and outcome

OBJECTIVES

To evaluate the detection rate of congenital heart defects (CHD) in a non-selected population and to follow outcome after diagnosis.

METHODS

All 30,149 fetuses/newborns that were scheduled to deliver at our hospital between February 1991 and December 2001 were registered prospectively. Of these, 29,460 (98%) fetuses had a prenatal ultrasound scan at our center. The routine fetal examination at approximately 18 weeks' gestation included the four-chamber view and the great arteries of the fetal heart. The follow-up period was 2-13 years.

RESULTS

Of 97 major CHDs, 55 (57%) were detected prenatally, 16% (9/55) prior to, 66% (36/55) at and 18% (10/55) after the routine scan. Forty-four percent (19/43) of the isolated CHDs, 67% (36/54) of those with associated malformations and 48% (11/23) of the isolated ductal-dependent CHDs were detected. Thirty-eight percent (37/97) had an abnormal karyotype. Of the 55 major CHDs detected, 44% (24) of the pregnancies with lethal/serious fetal malformations were terminated, 15% (8) died in utero, 42% (23) were born alive and 27% (15) were still alive after 2 years. Of the 42 CHDs detected postnatally, 2% (1) were terminated for other reasons, 98% (41) were born alive and 81% (34) were still alive after 2 years.

CONCLUSIONS

Prenatal detection of CHD is still a challenge, with a 57% detection rate only. Isolated defects are detected less frequently. The overall outcome suggests that the most severe defects are detected with the present screening setting; only 27% of the babies with major CHDs detected were still alive after 2 years. Data from long-term follow-up will be of importance for the counseling process.

Trends in fetal echocardiography and implications for clinical practice: 1985 to 2003

OBJECTIVE

The purpose of this study was to determine whether patterns of referral for fetal echocardiography (FE) and the subsequent yield for structural congenital heart disease (CHD) have changed between 1985 and 2003.

METHODS

All FE performed between 1985 and 2003 at Yale-New Haven Hospital was reviewed. The primary indication for study and the presence of structural CHD were recorded, and data were analyzed for trends. Linear regression with Pearson coefficient calculation and Mantel-Haenszel chi(2) analysis were performed (P < .05 significant).

RESULTS

Between 1985 and 2003, 10,806 patients had FE at Yale-New Haven Hospital, and 774 cases of structural CHD were detected. The annual number of studies and rate of detected structural CHD remained constant through the study period. There was a significant increase in the proportion of studies for diabetes, maternal structural CHD, suspicious 4-chamber heart, and family history of cardiac disease. There was a significant decrease in the proportion of studies for a previous child with structural CHD, cardiac teratogen exposure, other fetal anomalies, aneuploidy, fetal arrhythmia, and nonimmune hydrops. The percentage of structural CHD detected by indication remained constant through the study period. Subgroup analysis of diabetes revealed an increase in class B diabetes, while classes C and D remained stable.

CONCLUSIONS

This is one of the largest series of FE and suggests that the pattern of indications has changed since 1985. Specifically, referral for diabetes (mostly class B) has increased without a change in yield of structural CHD by indication for sonography. The changing referral patterns reflect a change in obstetric demographics and has implications for obstetric care.

Is the nuchal index increased in fetuses with congenital structural heart defects?

OBJECTIVES

To determine if the Nuchal index (NIx) is increased in euploid fetuses with structural congenital heart defects (CHD).

METHODS

Euploid fetuses with CHD between 18 and 24 weeks gestation were identified. The next fetus meeting the same criteria with a normal fetal echocardiogram were selected as a control. The NIx [(mean nuchal thickness /mean biparietal diameter) x 100] and cardiac axis (CA; degrees) were calculated for each fetus. Standard descriptive tests and two-tailed t test were used.

RESULTS

The NIx in the abnormal (n = 20) and control (n = 20) groups were 9.10 (2.35) and 7.54 (p = 0.04) and CA was 55.8 degrees and 48.6 degrees (p = 0.02), respectively.

CONCLUSIONS

The NIx and CA were significantly different in fetuses with CHD. A prospective study to confirm these findings and determine clinical utility is warranted.

Utility of fetal echocardiogram in high-risk patients

AIM

Patients at high risk of fetal congenital heart disease are commonly referred for second trimester fetal echocardiogram. The objective of this study was to evaluate the utility of routine fetal echocardiogram in high-risk patients after the evaluation of the four-chamber/left ventricular outflow tract (LVOT) views during comprehensive second trimester anatomy ultrasound.

METHODS

Second trimester comprehensive anatomy ultrasounds, which included a four-chamber/LVOT view, and subsequent fetal echocardiograms carried out at the Duke University Medical Center from January 1995 and July 2002 were reviewed. Those fetal echocardiograms carried out between 17 and 30 weeks gestation were included in the analysis.

RESULTS

A total of 725 individual subjects met the inclusion criteria. Twenty-nine fetal echocardiograms were ultimately reported as abnormal. Of these, 19 had an abnormal four-chamber/LVOT view, four had a suboptimal view and six had a normal view. Of the six patients with a normal four-chamber/LVOT, all had been referred for echocardiogram based on the presence of other significant fetal anomalies noted at the time of second trimester anatomy ultrasound (3), documented aneuploidy (2), and significant fetal arrhythmia (1).

CONCLUSION

Utility in carrying out fetal echocardiogram was seen in patients with an abnormal four-chamber/LVOT view, a suboptimal view in a high-risk patient, and the presence of other significant fetal abnormalities. Utility was not seen in patients with pre-existing diabetes mellitus.

Elevated first-trimester nuchal translucency increases the risk of congenital heart defects

OBJECTIVE

We sought to evaluate the association between first trimester nuchal translucency measurement and the risk for major congenital heart defect in chromosomally normal fetuses.

STUDY DESIGN

First trimester (10 weeks 4 days of gestation to 13 weeks 6 days of gestation) nuchal translucency was obtained in a large prospective multicenter National Institute of Child Health and Human Development study for Down syndrome prediction. The study, which was conducted between May 1998 and December 2000, was restricted to singleton pregnancies. Gestational age was determined by crown rump length measurements. Perinatal outcomes were determined and included the frequency of major congenital heart defect, which was defined as those cases that potentially could require surgery, intensive medical therapy, or prolonged follow-up time. Logistic regression analysis was used to determine whether nuchal translucency was a significant predictor of congenital heart defect.

RESULTS

There were 8167 chromosomally normal pregnancies, of which 21 cases of major congenital heart defect were identified at follow-up examination (incidence, 2.6/1000 pregnancies). The risk of congenital heart defect rose with increasing nuchal translucency measurements. The mean nuchal translucency value for the normal and congenital heart defect groups were 1.5 mm and 1.9 mm, respectively (P = .05). With a nuchal translucency measurement of < 2.0 mm, the incidence of congenital heart defect was 13 of 6757 pregnancies (1.9 of every 1000 pregnancies). At 2.0 to 2.4 mm, the incidence was 5 of 1032 pregnancies (4.8 of every 1000 pregnancies). At 2.5 to 3.4 mm, the incidence was 2 of 335 pregnancies (6.0 of every 1000 pregnancies). At > or = 3.5 mm, the incidence was 1 of 43 pregnancies (23 of every 1000 pregnancies). Logistic regression analysis confirmed that nuchal translucency was associated significantly with congenital heart defect (odds ratio, 2.1; 95% CI, 1.4-3.1; P = .0004).

CONCLUSION

Increased first trimester nuchal translucency measurement was associated with a higher risk of major congenital heart defect in chromosomally normal pregnancies. The practical implications of our findings are that patients with unexplained elevations of nuchal translucency may need referral for a fetal echocardiogram.

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.

First-trimester fetuses with increased nuchal translucency do not show altered intracardiac flow velocities

OBJECTIVE

To study intracardiac flow velocities in first-trimester fetuses with normal nuchal translucency thickness (NT) and those with increased NT.

METHODS

Ultrasound examinations were performed in 85 normal fetuses and 45 fetuses with NT > 95(th) percentile. Follow-up was complete and postmortem examination was performed on terminated pregnancies. Flow velocities during the early (e-wave) and late (a-wave) peaks across the tricuspid and mitral valves were measured and compared, using multilevel analysis, between the fetuses with normal and those with increased NT. In the group with increased NT, fetuses with and without a heart defect irrespective of the karyotype were compared, and in this group, euploid and aneuploid fetuses were compared, irrespective of the presence of a heart defect.

RESULTS

No difference in intracardiac flow velocities was found between fetuses with normal and those with increased NT. Within the group of fetuses with increased NT, there was no difference between the fetuses with and without a cardiac defect. However, comparison of aneuploid with euploid fetuses within the group with increased NT showed that both the e-wave and a-wave peaks were decreased significantly by 3.03 cm/s and 5.95 cm/s, respectively, across the tricuspid valve, and by 3.47 cm/s and 5.92 cm/s, respectively, across the mitral valve (P < 0.05). The most common cardiac malformations were septal defects.

CONCLUSION

There is no difference in intracardiac blood flow velocities between normal fetuses and those with increased NT. This contradicts the theory that NT is caused by impaired atrial contraction or cardiac failure. In fetuses with increased NT, those with aneuploidy show a decreased e-wave and a-wave compared with euploid fetuses. This cannot, however, be explained by the presence of cardiac defects, because there is no difference between fetuses with and without a cardiac defect. Therefore, we hypothesize that the relationship between enlarged NT and cardiac defects can only be explained by a developmental process that coexists at this period of gestation and is linked to cardiovascular development.

Abnormal lymphatic development in trisomy 16 mouse embryos precedes nuchal edema

Ultrasound measurement of increased nuchal translucency is a method of risk assessment for heart malformations and trisomy 21 in human pregnancy. The developmental background of this nuchal edema is still not sufficiently understood. We have studied the process in trisomy 16 mice that show nuchal edema and heart malformations. We used trisomy 16 and wild-type (WT) embryos from embryonic day (E) 12.5 to E18.5. In WT embryos at E13, bilateral jugular lymphatic sacs are visible that share a lymphatic-venous membrane with the jugular vein. We could not in any case discern a valve between these vessels. At E14 in the TS16 embryos, the lymphatic sacs become enlarged showing abnormally thickened endothelium, specifically at the site of the membrane. In these embryos, severe edema develops in the nuchal region. There is a very close colocalisation of the nerves with the vascular structures. The start of reorganization of the jugular lymphatic sac to a lymph node is observed in both wild-type and TS16 but is diminished in the latter. In conclusion, abnormal size and structure of the jugular lymphatic sacs coincides with the development of nuchal edema. A disturbance of lymphangiogenesis might be the basis for increased nuchal translucency that is often observed in diseased human fetuses.

Early detection of fetal structural abnormalities

Most published data on the detection of fetal anomalies at 11-14 weeks are from specialized centres with considerable experience in fetal anomaly scanning. However, there is still limited information on the feasibility and limitations of the screening of these anomalies compared with the now classical mid-gestation screening. This review indicates that overall, the detection rate of fetal anomalies at 11-14 weeks is 44% compared with 74% by the mid-pregnancy scan. Major abnormalities of the fetal head, abdominal wall and urinary tract, and of the umbilical cord and placenta, can be reliably detected at 10-11 weeks of gestation. Detection of other anomalies such as spina bifida, diaphragmatic hernia or heart defects is limited before 13 weeks of gestation. So far it cannot be stated that routine first trimester screening can be used on a large scale to evaluate the fetal spine and heart in the general population. In particular, in screening for congenital heart defects, the ability to perform a full cardiac examination increases from 20% at 11 weeks to 92% at 13 weeks. The early prenatal diagnosis of these anomalies may be improved by screening at 13-14 weeks rather than during the first trimester.

First-trimester maternal serum PAPP-A and free-beta subunit human chorionic gonadotropin concentrations and nuchal translucency are associated with obstetric complications: a population-based screening study (the FASTER Trial)

OBJECTIVE

The purpose of this study was to determine whether maternal serum levels of pregnancy-associated plasma protein A, free-beta subunit human chorionic gonadotropin, or nuchal translucency size are associated with obstetric complications.

STUDY DESIGN

Data were obtained from the First and Second Trimester Evaluation of Risk trial. Pregnancy-associated plasma protein A and free-beta subunit human chorionic gonadotropin levels were analyzed, and nuchal translucency was measured between 10 weeks 3 days and 13 weeks 6 days of gestation in 34,271 pregnancies.

RESULTS

Women with pregnancy-associated plasma protein A of < or =5th percentile were significantly more likely to experience spontaneous fetal loss at < or =24 weeks of gestation, low birth weight, preeclampsia, gestational hypertension, preterm birth ( P < .001) and stillbirth, preterm premature rupture of membranes, and placental abruption ( P < .02). Nuchal translucency at > or =99th percentile and free-beta subunit human chorionic gonadotropin at < or =1st percentile were associated with an increased risk of spontaneous loss at < or =24 weeks of gestation (adjusted odds ratios, 3.90, 3.62, respectively; P < .001).

CONCLUSION

Low pregnancy-associated plasma protein A levels in the first trimester were associated strongly with a number of adverse pregnancy outcomes. Low free-beta subunit human chorionic gonadotropin levels and large nuchal translucency were both associated with early fetal loss.

Clinical impact of first and early second trimester fetal echocardiography on high risk pregnancies

OBJECTIVE

To evaluate the clinical impact of fetal echocardiography before 16 weeks' gestation on the management of pregnancies with fetuses at risk of congenital heart disease.

DESIGN AND SETTING

Observational study in a fetal medicine unit.

PARTICIPANTS AND METHODS

222 consecutive women with high risk pregnancies (230 fetuses) underwent transabdominal fetal echocardiography at a median gestation of 14(+1) weeks. For 10%, transvaginal scans were also performed. Criteria for normal scans were normal sequential segmental analysis, symmetrical four chamber view, normal semilunar valves, arterial outflow tracts, and ductal and aortic arches. Early scans were compared with mid-second trimester fetal echocardiography. Postmortem and postnatal data were added. Adverse pregnancy outcomes were diagnosis of a major cardiac or extracardiac abnormality, chromosomal defects, intrauterine death, or termination of pregnancy.

RESULTS

There were 21 abnormal cardiac scans (9%): 14 major structural defects (eight isolated, six with chromosomal or extracardiac abnormalities) in pregnancies resulting in three live births, one intrauterine death, and 10 terminated pregnancies. Seven scans showed asymmetry between right and left sided structures (two isolated, five with chromosomal or extracardiac abnormalities); six of the seven pregnancies were terminated. The scans were normal in 199 cases (87%). Cardiac follow up of 184 of 199 babies (93%) confirmed situs and connections. One case each of pulmonary stenosis and ventricular septal defect requiring postnatal intervention were diagnosed at later scans. In 28 of 199 (14%) babies there was a non-cardiac adverse outcome. First examination was not diagnostic for 10 (4%).

CONCLUSION

Early fetal echocardiography in high risk pregnancies was diagnostic in 96%. Abnormal cardiac scans (isolated in 48%, major structural defects in 67%) led to termination of pregnancy in 76%. Most cardiac scans were normal, allowing family reassurance. The high number of adverse outcomes with normal cardiac anatomy stresses the need for a multidisciplinary approach to early fetal echocardiography.

Disappearance of enlarged nuchal translucency before 14 weeks' gestation: relationship with chromosomal abnormalities and pregnancy outcome

OBJECTIVE

The aim of this study was to investigate the natural course of enlarged nuchal translucency (NT) and to determine if its disappearance before 14 weeks' gestation is a favorable prognostic sign in relation to fetal karyotype and pregnancy outcome.

METHODS

A total of 147 women with increased NT (> 95th centile) at first measurement were included in this study. A second measurement was performed in all cases, at an interval of at least 2 days. Both measurements were taken between 10 + 3 and 14 + 0 weeks. All women underwent chorionic villus sampling or amniocentesis for subsequent karyotyping. In those women with a normal karyotype, a fetal anomaly scan was performed at 20 weeks' gestation. Pregnancy outcome was recorded in all cases. The finding of persistent or disappearing NT enlargement was analyzed in relation to fetal karyotype and pregnancy outcome.

RESULTS

Of the 147 paired measurements, NT remained enlarged at the second measurement in 121 (82%) cases. An abnormal karyotype was found in 35% of these cases. In 26 (18%) fetuses the NT measurement was found to be below the 95th percentile at the second measurement and in only two of them an abnormal karyotype was found (8%). In the 103 chromosomally normal fetuses an adverse outcome (i.e. fetal loss or structural defects) was recorded in 22 fetuses with persistent enlargement (28%) and in four fetuses with disappearing enlargement (17%).

CONCLUSIONS

Disappearance of an enlarged NT before 14 weeks' gestation is not a rare phenomenon and seems to be a favorable prognostic sign with respect to fetal karyotype. Overall, no significant difference in pregnancy outcome was found between chromosomally normal fetuses with persisting or disappearing NT enlargement.

Nuchal translucency and other first-trimester sonographic markers of chromosomal abnormalities

There is extensive evidence that effective screening for major chromosomal abnormalities can be provided in the first trimester of pregnancy. Prospective studies in a total of 200,868 pregnancies, including 871 fetuses with trisomy 21, have demonstrated that increased nuchal translucency can identify 76.8% of fetuses with trisomy 21, which represents a false-positive rate of 4.2%. When fetal nuchal translucency was combined with maternal serum free-beta-human chorionic gonadotropin and pregnancy-associated plasma protein-A in prospective studies in a total of 44,613 pregnancies, including 215 fetuses with trisomy 21, the detection rate was 87.0% for a false-positive rate of 5.0%. Studies from specialist centers with 15,822 pregnancies, which included 397 fetuses with trisomy 21, have demonstrated that the absence of the nasal bone can identify 69.0% of trisomy 21 fetuses, which represents a false-positive rate of 1.4%. It has been estimated that first-trimester screening by a combination of sonography and maternal serum testing can identify 97% of trisomy 21 fetuses, which represents a false-positive rate of 5%, or that the detection rate can be 91%, which represents a false-positive rate of 0.5%. In addition to increased nuchal translucency, important sonographic markers for chromosomal abnormalities, include fetal growth restriction, tachycardia, abnormal flow in the ductus venosus, megacystis, exomphalos and single umbilical artery. Most pregnant women prefer screening in the first, rather than in the second, trimester. As with all aspects of good clinical practice, those care givers who perform first-trimester screening should be trained appropriately, and their results should be subjected to external quality assurance.

Fetal heart scanning in the first trimester

The detailed study of the fetal cardiac anatomy in the first trimester of pregnancy by means of ultrasound, transvaginally or transabdominally, is feasible and remains a safe procedure provided thermal and mechanical indices are taken into account. Optimal time for successful imaging of the four chambers and great arteries in early gestation appears to be between 13 to 14 weeks. In experienced hands, first-trimester fetal echocardiography is accurate in detecting major structural cardiac abnormalities and yields a high negative predictive value. Thus, in a clinical setting, it can be offered to families considered to be 'at risk' of cardiac defects (e.g. those with previous family history or when fetal nuchal translucency is increased) and can be a powerful tool to reassure families regarding normality of major cardiac structures and connections. However, the early detection of an important structural abnormality (chromosomally normal or not) may be associated with a high termination rate if this is an acceptable option. The high prevalence of associated chromosomal and extracardiac abnormalities for many of the high-risk families, who may benefit from this approach, cannot be ignored. Therefore, fetal heart scanning in the first trimester should be performed in conjunction with detailed first-trimester obstetric scanning.

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.

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

OBJECTIVE

To determine the accuracy and practicality of fetal echocardiography in the identification of structural and functional cardiac abnormalities prior to 16 weeks' gestation in fetuses with increased nuchal translucency thickness (NT).

METHODS

Between January 1996 and June 2002 early fetal echocardiography using the transvaginal route was performed at 12-16 weeks' gestation on 275 fetuses with increased NT. The abnormal cardiac findings were classified as either structural (congenital heart defects) or functional, defined as transient phenomena which might later disappear, such as isolated tricuspid regurgitation and an enlarged ascending aorta. The abnormal findings were related to pregnancy outcome, including autopsy results, karyotyping results, and late fetal and neonatal echocardiography.

RESULTS

Cardiac abnormalities were present in 61 fetuses overall (22.2%); including structural cardiac defects in 37 fetuses (13.5%) and functional abnormalities in 24 fetuses (8.7%). Structural cardiac abnormalities were associated with abnormal karyotype in 24 fetuses and normal karyotype in 13 fetuses. Of the 24 fetuses with functional cardiac abnormalities, 2 (8.3%) had isolated tricuspid regurgitation and 22 (91.7%) had enlarged ascending aorta. Abnormal karyotype was present in this group in 4 cases (16.7%).

CONCLUSION

Increased NT can be used to define a high-risk group that should receive specialized early fetal echocardiography. This is a reliable technique with great potential for the diagnosis of both structural and functional cardiac abnormalities.

Tricuspid regurgitation in the diagnosis of chromosomal anomalies in the fetus at 11-14 weeks of gestation

OBJECTIVE

To analyse patient data to elucidate the apparent association between an abnormal karyotype and tricuspid regurgitation found during fetal echocardiography at early gestations.

SETTING

Tertiary referral centre for fetal medicine and cardiology.

METHODS

Fetuses between 11 and 14 weeks' gestation were selected for detailed echocardiography. Referral reasons were increased nuchal translucency, a suspected cardiac or extracardiac malformation, and a family history of cardiac malformation.

INTERVENTION

The fetus was imaged transabdominally. The four chamber view, outflow tracts, arterial duct, and aortic arch were assessed on cross sectional imaging and colour flow mapping. Pulsed Doppler of the atrioventricular valves was recorded if possible. Subsequently, the fetal karyotype was ascertained by chorionic villous sampling.

RESULTS

Pulsed Doppler recording of the tricuspid valve was obtained for 262 fetuses. Tricuspid regurgitation was present in 70 (27%) of these, of whom 58 (83%) proved to have karyotype anomalies. In contrast, 68 (35%) of those without tricuspid regurgitation were found to have karyotype anomalies (95% confidence interval 36% to 59%, p < 0.001). Structural heart defects were detected in 34 of the 58 (59%) with tricuspid regurgitation and in 22 (32%) of those without. The chromosome defect most frequently found to be associated with tricuspid regurgitation was trisomy 21, but all types of karyotypic anomalies were seen in association.

CONCLUSION

A careful search for tricuspid regurgitation is an important aspect of the evaluation of the early fetus, as this is frequently a marker for chromosomal defects even in the absence of structural heart disease.

Ductus venosus flow velocities in relation to the cardiac defects in first-trimester fetuses with enlarged nuchal translucency

OBJECTIVE

Our aim is to study first-trimester ductus venosus (DV) velocities in relation to cardiac abnormalities.

STUDY DESIGN

Ultrasound examination was performed in 85 normal fetuses and 45 fetuses with a nuchal translucency (NT) >95th percentile. Pulsatility index for veins (PIV) and velocity during late diastole (a-V) of the DV were measured and compared with the use of multilevel analysis, between fetuses with a heart defect and those without.

RESULTS

Compared with 85 normal fetuses, the a-V and PIV of the fetuses with NT>95th percentile and normal hearts were decreased and increased, respectively. The a-V and PIV of 11 fetuses with NT>95th percentile and cardiac defects were decreased and increased compared with the 25 fetuses with normal hearts, irrespective of the karyotype. The most common cardiac malformations were septal defects.

CONCLUSION

Fetuses with NT >95th percentile and cardiac defects show markedly changed DV velocities. Because the type of cardiac defects cannot always explain the hemodynamic changes found in these fetuses, some other mechanisms seem to be involved.

First-trimester nuchal translucency measurement and echocardiography at 16 to 18 weeks of gestation in prenatal detection for trisomy 18

BACKGROUND

Trisomy 18, the second most common autosomal trisomy, has the highest incidence of congenital heart disease of all chromosomal abnormalities. This study assessed the use of nuchal translucency (NT) measurement and fetal echocardiography at 16 to 18 weeks of gestation in prenatal detection for trisomy 18.

METHODS

Screening for chromosomal aneuploidy using fetal NT measurement was performed at 10 to 14 weeks of gestation. Detailed fetal echocardiography was performed at 16 to 18 weeks of gestation immediately before genetic amniocentesis for fetal karyotyping in singleton pregnancies with increased fetal NT thickness.

RESULTS

Of the 3151 singleton pregnancies included in our study, 171 cases (5.4%) of increased (> or =3.0 mm) NT were noted. Fetal chromosomal abnormalities were identified in 22 (12.9%) of these pregnancies, including 9 with trisomy 21, 5 with trisomy 18, 4 with 45,X and 4 with unbalanced structural abnormalities. Major defects of the heart and the great arteries were identified in 13 (7.6%) of these pregnancies with increased NT. These included eight pregnancies that also had the diagnosis of chromosomal aneuploidy. Among the 22 fetuses with confirmed aneuploidy, all 5 fetuses with trisomy 18, 1 of the 4 fetuses with 45,X and 2 of the 9 fetuses with trisomy 21 had increased fetal NT thickness associated with abnormal fetal echocardiography findings.

CONCLUSIONS

Screening for Down syndrome and cardiac defects using first-trimester fetal NT measurement in combination with fetal echocardiography at 16 to 18 weeks of gestation is a feasible and sensitive procedure for the prenatal detection of trisomy 18.

Cardiac defects in chromosomally normal fetuses with increased nuchal translucency at 10-14 weeks of gestation

OBJECTIVE

To examine the prevalence, distribution and spectrum of cardiac defects in chromosomally normal fetuses with increased nuchal translucency thickness.

PATIENTS AND METHODS

During a 4-year period, targeted fetal echocardiography was used in 353 chromosomally normal fetuses with increased nuchal translucency thickness at 10-14 weeks' gestation. The cardiac scan was performed at 18-22 weeks. In the last 138 cases enrolled, an additional scan at 12-16 weeks was carried out. The follow-up included the findings at necropsy or in the pediatric examination. A complete follow-up was achieved in 97%.

RESULTS

Cardiac defects were present in 32 (9.1%) cases, increasing from 5.3% in those with a nuchal translucency thickness of > or = 95th centile (3.9 mm) to 24% when thickness > or = 6 mm (p < 0.001). In 31 cases (97%), the cardiac defect was diagnosed antenatally; in 24 cases (77%) this diagnosis was confirmed later. In the remaining seven cases, the autopsy examination was not available. A wide range of cardiac defects was observed, with the most common being atrioventricular septal defect and tricuspid atresia.

CONCLUSIONS

Euploid fetuses with increased nuchal translucency thickness have a significantly increased risk of cardiac defects. This is a marker of different types of heart anomalies and constitutes an additional indication for targeted fetal echocardiography. Most of the cardiac defects can be detected by fetal echocardiography.

Congenital erythropoietic porphyria (Günther's disease): two cases with very early prenatal manifestation and cystic hygroma

Congenital erythropoietic porphyria (CEP) or Günther's disease is the rarest form of the porphyrias. The disease is usually diagnosed at birth or during early infancy, but rarely in utero. We describe here the first two cases of very early prenatal expression of CEP with cystic hygroma diagnosed at 14 weeks in the first fetus and at 19 weeks in the second. Both fetuses presented with severe nonimmune hydrops fetalis as early as 19 and 22 weeks, associated with intrauterine growth retardation, hyperechogenic kidneys and bones. Amniotic fluid was dark brown and uro- and coproporphyrin I was dramatically increased. Molecular screening of the CEP gene detected heterozygous C73R mutation in both fetuses, the other parental mutation being as yet unknown.

Midtrimester nuchal thickness and the prediction of postnatal congenital heart defect

OBJECTIVE

The study was performed to determine the sensitivity of nuchal thickness measurements for the detection of congenital heart defects (CHD) and to develop an algorithm for estimating patient-specific risk of CHD.

STUDY DESIGN

Nuchal thickness measurements (expressed as multiples of the median) were obtained in 3,003 midtrimester fetuses in which postnatal evaluation of the heart was available. The sensitivity and false-positive rate of nuchal thickness threshold values for detecting CHD were used to calculate the area under the receiver operating characteristics curve. Stepwise logistic regression analysis was used to determine the significant predictors of heart defect among nuchal thickness and epidemiologic risk factors. Individual risk of CHD was calculated on the basis of background population risk of major CHD (estimated at 4.4 of 1,000) and the product of the likelihood ratios of the significant risk factors from the logistic regression.

RESULTS

There were 95 cases of confirmed CHD. Nuchal thickness was statistically significant for the prediction of CHD with an area under the curve = 0.58, P =.01. Nuchal thickness and prior child with CHD were the only significant predictors among the multiple risk factors for this disorder. Patient-specific risk estimates for CHD based on these two "markers" were calculated. It was accurate and improved the prediction of CHD, area under the curve = 0.63, P <.001, compared with nuchal thickness alone.

CONCLUSION

Midtrimester nuchal thickness measurement significantly detected postnatally confirmed CHD in chromosomally normal fetuses. We report for the first time a method for estimating individual patient risk of CHD.