Detection of fetal structural abnormalities by an 11-14-week ultrasound dating scan in an unselected Swedish population

BACKGROUND: To determine the detection rate of fetal structural abnormalities by a routine 11-14-week ultrasound scan for dating in an unselected pregnant population. METHODS: A prospective observational cohort study of 2,708 unselected pregnant women attending an abdominal ultrasound examination at 11-14 weeks gestation. The number of major fetal structural abnormalities diagnosed after birth was obtained from a computerized database at the same unit. RESULTS: Out of 2,708 pregnant women, 89 (3.3%) were found to have a missed abortion at the time of the ultrasound scan and 33 (1.2%) were diagnosed as twins. Thirteen major structural abnormalities were detected, three cases of anencephaly (one case also had a spina bifida), one case with hydranencephaly, one fetus with Dandy-Walker syndrome, two cases with gastroschisis, one case with a bilateral hydronephrosis, one case with a generalized hydrops, one fetus with multiple malformations, and three cystic hygromas. An additional 19 major structural defects were detected at birth. Four cases of neural tube defects and nine fetuses with congenital heart defects were diagnosed. The antenatal ultrasound detection rate was 40.6% (13/32). Nine patients had a nuchal translucency greater than 3.0 mm (excluding cystic hygromas); two of them had chromosomal abnormalities (trisomy 21 and trisomy 18). CONCLUSIONS: Fetal structural abnormalities were detected in 41% (95%CI = 24-59) of the cases in an unselected pregnant population at a routine 11-14-week ultrasound scan for dating purpose. Two out of nine fetuses with a nuchal translucency greater than 3.0 mm had a chromosomal abnormality.     

Prenatal screening and diagnosis of neural tube defects in England and Wales in 1985

A survey was carried out to determine the effect of prenatal screening and therapeutic abortion on births in 1985 with anencephaly and spina bifida in England and Wales. Maternal serum alpha-fetoprotein tests were done on 399,288 women (60 per cent of pregnant women): 4 per cent were reported as being screen-positive and 1 per cent had an amniocentesis. An estimated 534 pregnancies associated with anencephaly were terminated and an estimated 445 pregnancies associated with spina bifida (but without anencephaly) were terminated. Most (63 per cent) of the anencephalic pregnancies were first suspected from an ultrasound examination; 57 per cent of the spina bifida pregnancies were first suspected from a positive maternal serum alpha-fetoprotein test, 35 per cent by ultrasound, and the remaining 8 per cent by other means. The birth prevalence of anencephaly declined by 94 per cent between 1964-1972 and 1985, but when the terminations of pregnancy on account of having a fetus with anencephaly are added to the births the decline in prevalence was only 50 per cent. The birth prevalence of spina bifida declined by 68 per cent over the same period but when the terminations were added to the births the decline in prevalence was only 32 per cent. Among births with anencephaly 66 per cent had had no screening or diagnostic tests in early pregnancy, but in those that did nearly all were positive--usually in twin pregnancies where one fetus was affected but not the other. Among births with spina bifida, 48 per cent had no tests and in those that did the results were mainly negative.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prenatal sonographic findings in 207 fetuses with trisomy 21

OBJECTIVE: The objective was to evaluate the contribution of second trimester ultrasound examination to the prenatal diagnosis of trisomy 21 in 207 fetuses with this aneuploidy. The type and frequency of abnormal sonographic findings were determined. Possible multiple malformation patterns, characteristic of trisomy 21 were sought. STUDY DESIGN: Singleton fetuses that had prenatal sonography during the second trimester, then underwent cytogenetic evaluation in our institution, made up the study population. The sonographic findings of 207 fetuses with trisomy 21 were analyzed. RESULTS: Between 1990 and 2004, fetal karyotyping was performed in 22,150 patients for different indications. An abnormal karyotype was diagnosed in 514 cases (2.3%); among them 207 fetuses with trisomy 21 were detected (40.3%). Abnormal sonography was seen in 63.8% of the cases. Structural anomalies were detected in 28.5% of the trisomy 21 fetuses, among them cardiac defects (15.9%), central nervous system anomalies (14.5%), and cystic hygromas (6.8%) were the most common. Of the minor markers, increased nuchal translucency (28%), pyelectasis (20.3%), and shorter extremities (8.7%) were common findings. CONCLUSIONS: Appropriate diagnosis of structural anomalies, looking for relatively easily detectable minor markers and incorporating fetal echocardiography into the second trimester sonographic protocol, may increase the contribution of mid-trimester ultrasound examination to diagnosing trisomy 21.     

Fetal karyotyping after 28 weeks of gestation for late ultrasound findings in a low risk population

OBJECTIVE: To analyze the indications and the results of invasive testing for fetal karyotyping for ultrasound abnormality in the third trimester of pregnancy, when first- and second-trimester screening tests were negative. METHODS: Retrospective study of 171 consecutive pregnancies that underwent invasive testing after 28 weeks of gestation in 2 institutions between January 1999 and December 2001. Forty-one patients did not have any form of screening for fetal aneuploidy beforehand. One hundred and thirty of them had a normal first-trimester scan and a low risk of fetal aneuploidy by nuchal translucency and/or maternal serum screening and were included in the statistical analysis. RESULTS: Mean maternal age, gestational age at diagnosis and at invasive testing were 30.5 years; 29.3 weeks and 32.5 weeks respectively. Amniocentesis and fetal blood sampling were performed in 97 and 33 cases respectively.The most frequent indications for invasive testing in the third trimester were major fetal malformations (51%) and intrauterine growth restriction (19%) detected on routine second- or third-trimester ultrasound examination. Ultrasound markers of aneuploidy and polyhydramnios accounted for 17 and 11% of the indications respectively.Fetal karyotype was normal in 121/130 cases. A gene mutation was found in one case. The karyotype was abnormal in nine cases, including seven cases of aneuploidy (one Turner syndrome, three trisomy 18, and three trisomy 21) and two cases of structural chromosomal abnormalities (46,XX, del 4 p16.1 and 46,XX, dup1).One hundred cases resulted in the delivery of a normal baby. Thirty cases led to termination of pregnancy or intrauterine death due to major fetal malformations (N = 25), abnormal karyotype in six of these, and severe IUGR (N = 5) with normal karyotype. Fetal US markers of aneuploidy and isolated polyhydramnios were associated with a favorable outcome in all cases.A significant increase in the risk of chromosomal anomaly was seen when two or more anomalies were found, rising from 2% with one anomaly to 21% when two or more anomalies were present. CONCLUSION: In low risk patients, fetal karyotyping in the third trimester may be justified when the diagnosis of fetal malformation is made in the third trimester of pregnancy. Two or more anomalies increase the risk of fetal aneuploidy even with a negative-screening test in the first and second trimester of pregnancy.     

The impact of maternal serum alpha fetoprotein screening on open neural tube defect births in north-east Scotland

Over the three years period 1980-1982, 18 256 pregnancies in the Grampian Region of N-E Scotland including the islands of Orkney and Shetland were screened for raised levels of maternal serum alpha fetoprotein (MSAFP) in the second trimester. Thirty six cases of fetal open neural tube defect in singletons were detected (18 anencephaly and 18 spina bifida). Four additional cases of open spina bifida were associated with normal MSAFP levels although two of these were detected by amniotic fluid AFP measurement when amniocentesis was carried out because of previous NTD history. A further three cases of open spina bifida and two of anencephaly occurred in unscreened pregnancies. The MSAFP screening programme alone was thus instrumental in reducing the birth incidence of open neural tube defects by 36 out of 45 cases (80 per cent) in singletons.     

Isolated clubfoot diagnosed prenatally: is karyotyping indicated?

OBJECTIVE: To evaluate the appropriateness of fetal karyotyping after prenatal sonographic diagnosis of isolated unilateral or bilateral clubfoot. METHODS: We retrospectively reviewed a database of fetal abnormalities diagnosed by ultrasound at a single tertiary referral center from July 1994 to March 1999 for cases of unilateral or bilateral clubfoot. Fetuses who had additional anomalies diagnosed prenatally, after targeted sonographic fetal anatomy surveys, were excluded. Outcome results included fetal karyotype diagnosed by amniocentesis, or newborn physical examination by a pediatrician. RESULTS: During the 5-year period, 5,731 fetal abnormalities were diagnosed from more than 27,000 targeted prenatal ultrasound examinations. There were 51 cases of isolated clubfoot. The mean maternal age at diagnosis was 30.5 years. The mean gestational age at diagnosis was 21.6 weeks. Twenty-three of the women (45%) were at increased risk of fetal aneuploidy, on the basis of advanced maternal age or abnormal maternal serum screening. Six women (12%) had positive family histories of clubfoot; however, no cases of aneuploidy were found by fetal karyotype evaluation or newborn physical examination. All cases of clubfoot diagnosed prenatally were confirmed at newborn physical examination, and no additional malformations were detected. CONCLUSION: After prenatal diagnosis of isolated unilateral or bilateral clubfoot, there appeared to be no indication to offer karyotyping, provided that a detailed sonographic fetal anatomy survey was normal and there were no additional indications for invasive prenatal diagnoses.     

Maternal serum alpha-fetoprotein and previous neural tube defects.

A case-control study involving 63 pregnancies showed that women who had previously had an infant with anencephaly or spina bifida did not have raised serum alpha-fetroprotein (AFP) levels in subsequent unaffected pregnancies. The value of a serum AFP determination in such women is discussed. If the serum AFP level is normal and if ultrasonography excludes anencephaly the risk of spina bifida might be low enough (about 1 per cent) to make diagnostic amniocentesis difficult to justify. Conversely, a high serum AFP value in such women should not be acted on without confirmation of an abnormality by ultrasonography and, if that is negative, by diagnostic amniocentesis.     

Spina bifida--retrospective analysis of fetuses diagnosed in the department of obstetrics & gynecology of the postgraduate center of medical education between 1997 & 2004

OBJECTIVES: Our objectives were to determine the kind and localisation of the spina bifida and if open neural tube defects are associated with other anomalies and ventriculomegaly. DESIGN: We retrospectively studied ultrasound reports of the fetuses with open neural tube defects. MATERIALS AND METHODS: We analyzed 178 cases diagnosed during the last seven years in our center. All fetuses underwent a detailed ultrasonographic survey. We also analyzed gestational age at the first examination. RESULTS: Associated anomalies were detected in 78 cases, in 100 cases spina bifida was the only anomaly. Lumbo-sacral and sacral localisation was presented in 88% of spina bifida not related with other anomalies and in 50% of cases with associated anomalies. In 94.4% of cases the malformation was myelomeningocoele. Ventriculomegaly was present in 89.1%. The median gestational age at the first examination was 26 weeks. Before 24 week only 34.3% of examinations was done. CONCLUSIONS: In fetuses with spina bifida detailed ultrasonographic survey should be performed. Measurement of the lateral ventricules should be done in each examination. Furthermore patient with fetus with spina bifida should be diagnosed as early as possible in the referral center.     

Absent intracranial translucency--new ultrasound marker for spina bifida at 11-13+6 weeks of gestation

Spina bifida is the most common abnormality of the fetal central nervous system. Prenatal diagnosis is usually made by ultrasound in the second or third trimester of pregnancy. However, first trimester detection of spina bifida is still a challenge. A new indirect ultrasound sign of open spina bifida between 11-13 6 weeks of gestation (w.g.) has been recently described. The marker is associated with an absence of intracranial translucency (IT) in the mid-sagittal plane. We present a case report of an open spina bifida detected at 13+2 weeks of gestation with an absent IT. The main ultrasound characteristics of normal and absent IT are described. In addition, the diagnostic role of three-dimensional (3D) transvaginal ultrasound is also discussed.     

Neural tube defects in the sample of genetic counselling

OBJECTIVE: This study was conducted to evaluate the major demographic details, diagnostical and clinical features, as well as the risk of recurrence of cases with the major types of neural tube defects (NTD). We also examined the efficiency of ultrasonography based on autopsy examinations during 26 years. METHODS: The investigations were made into the sample of 743 NTD diagnosed between 1 January 1976 and 31 December 2002. A computerized database was used to sum up the available information about the individual cases; in addition to surveying the couples' major demographic details, we also had the opportunity to collect detailed information about the history, diagnostics (ultrasound) and outcome of the pregnancies as well as the results of the autopsies during the investigation. RESULTS: In the 743 cases of NTD, maternal and paternal median ages turned out to be 23.7 years (+/-5.22 years) and 28.7 years (+/-5.81 years), respectively. The male:female ratio was 0.78. Comparable samples of anencephaly and spina bifida allowed for the conclusion that a positive genetic history was equally often found while a positive obstetrical history was almost twice as common in anencephaly. The sensitivity of the maternal serum-alpha fetoprotein (AFP) screening test is the highest in anencephaly and lowest in encephalocele. While the majority of cases of anencephaly were diagnosed before the 24th gestational week, examples of diagnosing spina bifida and encephalocele at a later time could also be found. Among the associated malformations other than those of the central nervous system special mentioning should be made of fetal pyelectasia, cleft palate as well as diaphragmatic herniation. No pathological karyotypes were found in association with encephalocele or spina bifida, but anencephaly was accompanied with trisomy 21 and trisomy 18 in one case each. Anencephaly was found to have the highest risk of recurrence in both nervous system malformations and malformations other than those of the nervous system. Sonography proved to be the most reliable method in cases of enecephalocele. CONCLUSION: The respective median values of maternal and paternal age show that aetas has no role in the occurrence of NTDs. NTDs are more common among girls. Positive genetic, obstetrical and medical findings are of great importance in the incidence of NTDs. Although reliable to only a limited extent, maternal serum-AFP tests are considered to be useful and necessary in screening NTDs, while sonography is the gold standard method in recognizing these frequent malformations. The knowledge of the eventual associated malformations is mainly important in certain cases of spina bifida, which may also yield a good post-natal prognosis. Our data obtained from the sample of 26 years also confirm that the periconceptional administration of folic acid reduces the incidence and risk of recurrence of NTDs.     

Screening for fetal aneuploidies and fetal cardiac abnormalities by nuchal translucency thickness measurement at 10-14 weeks of gestation as part of routine antenatal care in an unselected population.

OBJECTIVES: To evaluate first trimester pregnancy screening for fetal aneuploidy and congenital heart defects by maternal age and nuchal translucency measurement and screening for fetal aneuploidies and congenital heart defects by ultrasound in an unselected population. DESIGN: A prospective study. SETTING: Fetal medicine unit, St George's Hospital, London. SAMPLE: 4523 consecutive viable fetuses at 10-14 weeks with a crown-rump length between 38 and 80 mm were scanned transabdominally (93%) or transvaginally (7%). METHODS: Screening was performed by calculating the background risk from maternal age, gestational age and obstetric history, which was then adjusted with the nuchal translucency measurement in relation to crown-rump length (adjusted risk). MAIN OUTCOME MEASURES: Measurements of crown-rump length and nuchal translucency thickness. An adjusted risk of > 1:270 was considered as a positive screening test. Pregnancy outcome was obtained through karyotyping, outcome questionnaires and examination of the newborn infants. RESULTS: Mean maternal age was 29-4 years and mean gestational age 12.2 weeks. Screening was positive in 230/4523 fetuses (5.1%), when the adjusted risk (mean 1:2649) was > 1:270. Fetal karyotype was abnormal in 23 (0.51%) cases, including twelve with trisomy 21, five trisomy 18, one trisomy 13, one trisomy 10, one monosomy X and two triploidies. For a false positive rate of 4.7%, the sensitivity of this test was 78% in detecting any fetal aneuploidy. Only one out of nine major congenital heart defects in this population was found within the 110 euploid fetuses with increased nuchal translucency thickness (> 2.5 mm). CONCLUSION: Screening for fetal aneuploidy by maternal age and nuchal translucency measurement can be effective in an unselected population. However, our results do not support its effectiveness in the detection of cardiac abnormalities.     

Postmortem evaluation of 220 prenatally diagnosed fetuses with neural tube defects: detection of associated anomalies in a Turkish population

OBJECTIVES: The aim of this study is to represent the distribution of disorders resulting from neural tube defects (NTDs). MATERIALS AND METHODS: This study was conducted on 220 prenatally diagnosed cases with NTDs. Fetuses were evaluated by physical examination, anthropometric measurements, X-rays, and photographs after termination of pregnancy. Chromosome analysis and autopsy were performed for 37 fetuses (16.8%) with additional malformations. RESULTS: In 29 out of 37 fetuses (78.4%), additional malformations were detected by prenatal ultrasonography, whereas in eight cases postmortem evaluation produced additional findings that were not detected prenatally. Fourteen of 37 (37.8%) and 65 of 220 (29.5%) fetuses had clubfoot, which was mostly secondary to NTDs. There was no difference in sex distribution between isolated NTDs and the group with additional abnormalities and among the groups anencephaly and anencephaly + anomaly, encephalocele and encephalocele + anomaly, spina bifida and spina bifida + anomaly. There was only one case, a female fetus, with iniencephaly in this group. Anencephaly was more frequent in cases with isolated NTDs (48.1%) than in those with additional anomalies (27%). There was no difference for other groups of NTDs. The most frequent disorder was vertebral segmentation defects, which were detected in 11 out of 37 cases (29.7%). CONCLUSIONS: Evaluation of associated malformations and confirmation of ultrasound findings can be performed by postmortem examination and simple X-ray studies for exact diagnosis, which strongly affects decisions on further pregnancies as well as genetic counseling. This method is straightforward, inexpensive and effective.     

Chromosomal anomalies and additional sonographic findings in fetuses with open neural tube defects

Objective

To evaluate the results and the necessity of chromosome analysis in fetuses prenatally detected with a neural tube defect and to determine the significance of ultrasonographic evaluation for the identification of underlying or accompanying chromosomal anomalies.

Methods

Ninety fetuses that underwent prenatal and/or postnatal chromosome analysis after being diagnosed with open neural tube defects (NTD) between the years 2006 and 2010 in the Department of Obstetrics and Gynecology at Ondokuz Mayis University School of Medicine were included in this study. Detailed fetal ultrasonography was performed in all cases in order to investigate any additional anomalies. Karyotype was determined in the prenatal period by amniocentesis in 72 (80?%) of the 90 fetuses, and by cordocentesis in 5 (5.5?%). In 13 (13.3?%) fetuses, karyotype was determined in the postnatal period by blood sampling.

Results

Fourteen (15.5?%) of the 90 fetuses were diagnosed with acrania/anencephaly, 14 (15.5?%) with encephalocele, 2 (2.2?%) with iniencephaly, 60 (66.6?%) with open spina bifida. None of the 90 fetuses with open NTD who had undergone chromosome analysis was diagnosed with chromosomal anomalies. None of the 19 (21.1?%) fetuses diagnosed with additional ultrasound findings had a chromosomal abnormality, either. Seventy-one (78.9?%) fetuses having sonograhically isolated NTD were also isolated in postmortem examination.

Conclusion

In fetuses with open NTD, we could not find the chromosomal anomaly rate as high as reported in previous literature. The necessity of fetal karyotyping should be questioned especially in isolated cases.     

Comparison of six sonographic signs in the prenatal diagnosis of spina bifida

AIMS: To compare the diagnostic accuracy of sonographic signs that may be looked for in fetuses with spina bifida. METHODS: Forty-nine fetuses affected by spina bifida were enrolled, at a gestational age of 18-28 weeks. The following sonographic signs were looked for: "lemon" sign, small cerebellum, effaced cisterna magna, small posterior fossa, ventriculomegaly and direct visualization of a spinal defect. RESULTS: The "lemon" sign was present in 53%, a small cerebellum in 96%, an effaced cisterna magna in 93%, a small posterior fossa in 96%. Ventriculomegaly was present in 40/49 (81%) cases and was severe in 20 fetuses and borderline in the remaining 20. The spinal defect was missed in one fetus presenting the cerebellar and posterior fossa signs. In two fetuses, the myelomeningocele was present without cranial signs of Chiari II malformation and in both cases the defect was covered by intact skin. CONCLUSIONS: Our results confirm the usefulness of evaluation of the posterior fossa in the diagnosis of spina bifida, particularly in cases of small spinal defects that may be missed at ultrasound. Conversely, myelomeningocele covered by intact skin was not associated with the cranial signs of Chiari II malformation.     

Maternal serum alpha-fetoprotein screening for open neural tube defects in twin pregnancies.

Data on maternal serum alpha-fetoprotein (AFP) levels at 13-24 weeks' gestation in 46 twin pregnancies with open neural tube defects (22 with anencephaly, 24 with open spina bifida) and 169 unaffected twins were used to estimate the detection and false-positive rates associated with different cut-off levels. Using the conventional cut-off level of 2.5 multiples of the median (MoM) for unaffected singleton pregnancies of the same gestation and laboratory, the detection rate in twins was 99 per cent for anencephaly and 89 per cent for open spina bifida, with a false-positive rate of 30 per cent. Using a 5.0 MoM cut-off level to maintain a similar false-positive rate to that found among singleton pregnancies at 16-18 weeks' gestation (about 3 per cent), the detection rate was 83 per cent for anencephaly and 39 per cent for open spina bifida. Estimates are provided of the odds of having an affected twin pregnancy given a positive AFP result as well as the odds for individual women with a raised AFP level.     

Pallister-Killian syndrome presenting through nuchal translucency screening for trisomy 21

Pallister-Killian syndrome (tetrasomy 12p) is an uncommon aneuploidy, which may present in the prenatal period with an ultrasonographically detected fetal abnormality or following karyotyping for maternal age. We report a case that presented with increased nuchal translucency and hydrops at a first trimester screening scan for trisomy 21.     

Screening for fetal chromosomal abnormalities with nuchal translucency measurement in the first trimester

OBJECTIVE: To describe the detection rate of first-trimester chromosomal abnormality screening with nuchal translucency (NT) measurement and maternal age in our population. METHODS: We have screened the fetuses between 11 to 14 weeks' gestation according to the Fetal Medicine Foundation's (London) instructions and used the FMF's software to assess the risk based on maternal age, crown-rump length (CRL) and NT. Fetal karyotyping was offered when screening for Down syndrome identified a risk greater than 1 in 300. Sensitivity and false-positive rates were calculated for different cut-offs. RESULTS: Pregnancy outcome was obtained from 4,598 babies of 4,365 mothers. The median maternal age of the 4,365 women was 28.2+/-5.3 (range 15-47) years, and the median fetal CRL was 65.4+/-9.4 (range 45-81) mm. There was risk estimate of >or=1 in 300 in 214 fetuses (4.7%). Chromosomal abnormalities were identified in 32 fetuses, including 19 cases of trisomy 21, and 13 cases of other abnormalities. The sensitivity using NT and maternal age in detecting trisomy 21 with a cut-off 1 in 300 was 73.6% (14/19) with a false-positive rate of 4.7%. At a false-positive rate of 3%, with a cut-off level 1 in 210, the detection rate was 73.6%. The detection rate for all chromosomal abnormalities with a cut-off level 1 in 300 was 68.8% (22/32) at a false-positive rate of 4.7%. CONCLUSION: The first-trimester screening for chromosomal anomalies with NT measurement, when carried out according to the accepted standards of quality, is useful.     

Screening for fetal aneuploidies and fetal cardiac abnormalities by nuchal translucency thickness measurement at 10–14 weeks of gestation as part of routine antenatal care in an unselected population

Objectives To evaluate first trimester pregnancy screening for fetal aneuploidy and congenital heart defects by maternal age and nuchal translucency measurement and screening for fetal aneuploidies and congenital heart defects by ultrasound in an unselected population.
Design A prospective study.
Setting Fetal medicine unit, St George's Hospital, London.
Sample 4523 consecutive viable fetuses at 10–14 weeks with a crown–rump length between 38 and 80 mm were scanned transabdominally (93%) or transvaginally (7%).
Methods Screening was performed by calculating the background risk from maternal age, gestational age and obstetric history, which was then adjusted with the nuchal translucency measurement in relation to crown–rump length (adjusted risk).
Main outcome measures Measurements of crown–rump length and nuchal translucency thickness. An adjusted risk of > 1:270 was considered as a positive screening test. Pregnancy outcome was obtained through karyotyping, outcome questionnaires and examination of the newborn infants.
Results Mean maternal age was 29.4 years and mean gestational age 12.2 weeks. Screening was positive in 230/4523 fetuses (5.1%), when the adjusted risk (mean 1:2649) was > 1:270. Fetal karyotype was abnormal in 23 (0.51%) cases, including twelve with trisomy 21, five trisomy 18, one trisomy 13, one trisomy 10, one monosomy X and two triploidies. For a false positive rate of 4.7%, the sensitivity of this test was 78% in detecting any fetal aneuploidy. Only one out of nine major congenital heart defects in this population was found within the 110 euploid fetuses with increased nuchal translucency thickness (> 2.5 mm).
Conclusion Screening for fetal aneuploidy by maternal age and nuchal translucency measurement can be effective in an unselected population. However, our results do not support its effectiveness in the detection of cardiac abnormalities.     

The genetic sonogram: its use in the detection of chromosomal abnormalities in fetuses of women of advanced maternal age

Real-time and color Doppler ultrasound were used to examine 103 second trimester fetuses with abnormal chromosomes (trisomies 13, 18, 21 and sex aneuploidy =86; other =17) and 2000 controls from women of advanced maternal age who electively underwent genetic amniocentesis. Ten ultrasound markers were analyzed and likelihood ratios were computed for each abnormal ultrasound finding and for a normal ultrasound study if none of the ten markers were present. Abnormal ultrasound markers were present in 81% of fetuses with abnormal karyotypes. The false-positive rate was 13%. The likelihood ratios and the 5% and 95% confidence limits for each of the ultrasound markers were as follows: choroid plexus cyst(s) 1.5 (0.7-3.6); central nervous system abnormalities 16.2 (4.4-60.3); abnormal nuchal skin fold 20.9 (8.4-52.1); ventricular septal defect 8.3 (4.7-14.9); outflow tract defects of the heart 3.6 (0.9-14.6); right-to-left chamber disproportion of the heart 36.9 (14.4-94.5); pericardial effusion 7.2 (3.2-16.1); tricupsid regurgitation 4.7 (2.1-10.7); hyperechoic bowel 3.7 (1.8-7.7); and pyelectasis 2.7 (1.0-7.7). All ultrasound markers were independent of each other. The likelihood ratio following a normal ultrasound study was 0.20. Isolated ultrasound markers were present in 20.4% (n=21) of fetuses. When all markers were compared to non-cardiovascular markers, the detection rate for fetuses with a chromosomal abnormality decreased from 81% to 52% (p<0.01). Given the above data, the posterior risk following an ultrasound examination using the ultrasound markers evaluated in this study can be used to compute the risk for an abnormal karyotypes in women of advanced maternal age.