Strawberry-shaped skull in fetal trisomy 18.

During an 8-year period, a strawberry-shaped skull (flattening of the occiput with pointing of the frontal bones), was observed in 54 (3%) of the 2,086 fetuses that underwent karyotyping in our unit because of fetal malformations and/or growth retardation. In all 54 cases with a strawberry-shaped skull, there were other fetal malformations; in 43 (80%) fetuses, there was trisomy 18 and in 1 triploidy. Therefore, the ultrasonographic finding of a strawberry-shaped skull should initiate a diligent search for the presence of other markers of trisomy 18 and is a strong indication for fetal karyotyping. However, in the total series of 2,086 fetuses with malformations and/or growth retardation, there were another 40 fetuses with trisomy 18 and 41 with triploidy who did not have a strawberry-shaped skull.     

First trimester umbilical artery pulsatility index in fetuses presenting enlarged nuchal translucency

The aim of this prospective study was to evaluate an umbilical artery pulsatility index (UAPI) in first trimester fetuses who present enlarged nuchal translucency (NT) measurements. UAPI was measured in 121 single fetuses with NT > or =95th centile, from 10+3 to 13+6 weeks (crown-rump length (CRL) > or =38 mm - < or =84 mm). In these fetuses there were 20 trisomy 21, and six other chromosomal abnormalities (three trisomy 18 and three monosomy X). Eighty-nine cases had normal karyotype and delivered a baby without evidence of congenital malformations. Five fetuses with normal karyotype assessed antenatally were excluded from the comparison, because of evidence of congenital malformation. A fetus with normal karyotype that was spontaneously miscarried at 14 weeks' after chorionic villus sampling was also excluded. UAPI of fetuses with enlarged NT was compared with those of 65 singleton fetuses with normal NT and normal karyotype, which were used to establish our terms of reference (5th centile, median and 95th centile). UAPI of 7/20 (35%) Down syndrome and 42/89 (47%) normal karyotype fetuses presenting enlarged NT were above the median, and respectively 2/20 (10%) and 14/89 (15.7%) were above 95th centile of normal NT and normal karyotype fetuses. No significant differences were demonstrated in the UAPI values amongst normal karyotype fetuses with normal NT or normal karyotype fetuses with an enlarged NT or trisomy 21 fetuses with an enlarged NT.     

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.     

Relation between increased fetal nuchal translucency thickness and chromosomal defects

OBJECTIVE: To examine the prevalence and distribution of all chromosomal defects in fetuses with increased nuchal translucency thickness. METHODS: Assessment of risk for trisomy 21 was carried out by a combination of maternal age and fetal nuchal translucency thickness at 11-13 + 6 weeks. A search of the database was made to identify, first, all singleton pregnancies in which fetal karyotyping was carried out and, second, the cases where the fetal nuchal translucency was equal to or above the 95th centile for fetal crown-rump length. The prevalence and distribution of chromosomal defects were determined for each nuchal translucency category: between the 95th centile for crown-rump length and 3.4 mm, 3.5-4.4 mm, 4.5-5.4 mm, 5.5-6.4 mm, 6.5-7.4 mm, 7.5-8.4 mm, 8.5-9.4 mm, 9.5-10.4 mm, 10.5-11.4 mm, and 11.5 mm or more. RESULTS: The search identified 11,315 pregnancies. The median maternal age was 34.5 (range 15-50) years, and the median fetal crown-rump length was 64 (range 45-84) mm. The fetal karyotype was abnormal in 2,168 (19.2%) pregnancies, and the incidence of chromosomal defects increased with nuchal translucency thickness from approximately 7% for those with nuchal translucency between the 95th centile for crown-rump length and 3.4 mm to 75% for nuchal translucency of 8.5 mm or more. In the majority of fetuses with trisomy 21, the nuchal translucency thickness was less then 4.5 mm, whereas in the majority of fetuses with trisomies 13 or 18 it was 4.5-8.4 mm, and in those with Turner syndrome it was 8.5 mm or more. CONCLUSION: In fetuses with increased nuchal translucency, approximately one half of the chromosomally abnormal group is affected by defects other than trisomy 21. The distribution of nuchal translucency is different for each type of chromosomal defect. LEVEL OF EVIDENCE: II-3.     

Predictive value of increased nuchal translucency as a screening test for the detection of fetal chromosomal abnormalities

Objective.?The study aimed to estimate the incidence of increased nuchal translucency in the first trimester ultrasound scan results (cut-off limit 2.5 mm) and to evaluate the predictive value of increased nuchal translucency as a screening test for the detection of fetal chromosomal abnormalities.

Methods.?We used the ultrasound scan results of nuchal translucency evaluation and the results of chromosomal analysis of the invasive prenatal control performed as a result of increased nuchal translucency.

Results.?We collected 2183 nuchal translucency ultrasound scans in which we detected 21 embryos with a pathologic value (0.96%). We collected the data of 168 cases of invasive prenatal control due to increased nuchal translucency from which 122 cases were found. A total of 122 cases of pregnant women undergone an invasive prenatal diagnostic method due to increased nuchal translucency, of which 11 fetuses were found with trisomy 21 (Down syndrome) (9%), 3 fetuses with trisomy 13 (Patau syndrome) (2.45%), 3 fetuses with monosomy 45XO (Turner syndrome) (2.45%) and 1 fetus with translocation (0.8%).

Conclusions.?The positive predictive value of the increased fetal nuchal translucency as a screening test for the detection of fetal chromosomal abnormalities based on the results of the chromosomal-genetic analysis of the invasive prenatal diagnostic procedures is 14.8%.     

If nuchal translucency screening is combined with first-trimester serum screening the need for fetal karyotyping decreases

BACKGROUND: This case-control study was performed to evaluate whether adding first-trimester maternal serum testing to nuchal translucency measurement would improve the antenatal detection of Down's syndrome and decrease the number of women offered fetal karyotyping. METHODS: In the Swedish Nuchal Translucency Trial (the NUPP trial), 39,572 pregnant women were randomized to a routine scan at 12-14 gestational weeks including nuchal translucency screening for Down's syndrome, or a routine scan at 16-18 gestational weeks. From the early scan group 47 pregnancies with Down's syndrome were identified and for each case three controls were chosen. Of the 189 women asked to participate, 31 cases and 108 controls with a singleton pregnancy and frozen serum from 8-14 gestational weeks available for analysis accepted participation. Maternal sera were analyzed for free beta human chorionic gonadotrophin and pregnancy-associated plasma protein A. The risk for Down's syndrome was calculated using combinations of maternal age, crown-rump length, nuchal translucency, and biochemistry. A risk > or =1/250 was considered increased and an indication for fetal karyotyping. RESULTS: Risk calculated on the basis of maternal age alone would have identified 21 of the 31 Down's syndrome cases by karyotyping 61 of the 139 fetuses. Maternal age and nuchal translucency would have identified 29 cases by karyotyping 51 fetuses. Maternal age, nuchal translucency, and biochemistry would also have identified 29 cases by karyotyping 37 fetuses. CONCLUSIONS: By adding first trimester biochemistry to nuchal translucency measurement the detection rate of fetuses with Down's syndrome seems to remain unchanged whereas the antenatal risk group to be offered fetal karyotyping decreases.     

Increased fetal nuchal translucency thickness at 10–14 weeks: is screening for maternal–fetal infection necessary?

Objective To investigate the relation between increased fetal nuchal translucency thickness at 10–14 weeks of gestation and maternal–fetal infection.
Design Prospective study.
Setting Harris Birthright Research Centre for Fetal Medicine.
Population Four hundred and twenty-six chromosomally normal pregnancies with increased fetal nuchal translucency thickness at 10–14 weeks of gestation and 63 with 'unexplained' second or third trimester fetal nuchal oedema or hydrops.
Methods Maternal serum infection screening and investigations for fetal infection in those with evidence of recent maternal infection.
Main outcome measures Maternal and fetal infection.
Results Evidence of recent maternal infection was present in six of the 426 pregnancies (1.4%) with increased fetal nuchal translucency thickness at 10–14 weeks, but in all cases a healthy infant was born with no evidence of infection. In contrast,'unexplained' second or third-trimester fetal hydrops was associated with maternal infection in six of the pregnancies (9.5%) and in all cases there was evidence of fetal infection.
Conclusions Maternal–fetal infection is one of the causes of second or third trimester nuchal oedema or fetal hydrops. In contrast, the presence of increased nuchal translucency in the first trimester is not a marker of either maternal or fetal infection.     

First-trimester ductus venosus velocimetry in relation to nuchal translucency thickness and fetal karyotype.

AIM: To evaluate first-trimester ductus venosus flow in relation to nuchal translucency (NT) and fetal karyotype. METHODS: Ductus venosus flow was measured in fetuses with NT greater than or equal to the 95th centile (group A) and in fetuses with NT less than the 95th centile (group B). The waveforms were classified as normal if the lowest forward velocity during atrial contraction (ACV) was positive and abnormal if it was absent or negative. The results were compared with the fetal karyotype. RESULTS: Ductus venosus measurement was carried out in 330 fetuses. In group A, there were 156 fetuses: in 4 cases, it was not possible to obtain the measurement, and in the other 152 cases, 93 (61%) had a normal ACV and 59 (39%) an abnormal ACV. NT thickness was significantly greater in fetuses with abnormal ACV. In 34 out of 156 cases (22%), chromosomal abnormalities were found. Twenty-three chromosomopathies out of 33 (70%) had an abnormal ACV, and 10 (30%) had a normal ACV. A significant association between abnormal karyotype and abnormal ACV was found. Ductus venosus measurement was carried out in 174 fetuses of group B. In 1 case, it was not possible to obtain the measurement. One hundred and seventy-one (99%) cases had a normal ACV, and in 2 (1%) cases the ACV was abnormal. No chromosomal abnormalities were found in group B. Considering group A and group B, a significant association between the finding of an enlarged NT and abnormal ACV was detected (p < 0.05). CONCLUSIONS: An abnormal ACV is more frequent in fetuses presenting enlarged NT than in those having normal NTs and in fetuses having the larger nuchal thickness. The probability of having a chromosomal abnormality in fetuses with enlarged NT is greater when an abnormal ACV is found.     

Nuchal translucency and fetal cardiac defects: a pooled analysis of major fetal echocardiography centers

OBJECTIVE: Increased fetal nuchal translucency is associated with increased risk for congenital heart defects. In the present study, we aimed to investigate whether fetal nuchal translucency distribution differs among different types of congenital heart defects and whether it can lead to an earlier diagnosis. STUDY DESIGN: Four fetal echocardiography units provided data on fetuses with a congenital heart defect diagnosis in whom nuchal translucency thickness had been measured in the first trimester. Nuchal translucency data were compared per chromosomal status and type of congenital heart defect. Data on gestational age at diagnosis were also analyzed. RESULTS: Six hundred thirty-seven cases of congenital heart defect with known karyotype and exact nuchal translucency measurements were analyzed. Nuchal translucency was > or =3.5 mm in 22.9% of chromosomally normal fetuses (n = 397) and 58.8% of chromosomally abnormal cases (n = 240). Among fetuses with normal karyotype, the proportion of cases of congenital heart defect with increased nuchal translucency was similar in each of the subtypes of congenital heart defect (P = .96). Mean gestational age at diagnosis of congenital heart defect in fetuses with normal karyotype was 22.1 weeks with nuchal translucency of <3.5 mm and 16.1 weeks with nuchal translucency of > or =3.5 mm. CONCLUSION: Finding nuchal translucency of > or =3.5 mm may lead to an earlier diagnosis of all major types of congenital heart defects.     

Fetal lateral cerebral ventriculomegaly: associated malformations and chromosomal defects

In 267 consecutive cases of fetal lateral cerebral ventriculomegaly, additional fetal malformations were detected by ultrasonography in 209 (78%) of the cases. On the basis of the ultrasound findings, the patients were subdivided into three groups: (i) isolated ventriculomegaly (n = 58), (ii) ventriculomegaly and open spina bifida only (n = 172), and (iii) ventriculomegaly and other malformations (n = 37) with or without spina bifida. Antenatal karyotyping was performed in 64 cases from groups (i) and (iii), and 11 (18%) of the fetuses had chromosomal abnormalities. The incidence of chromosomal abnormalities was strongly related to the presence of multisystem malformations. Thus, only 3% of fetuses with isolated ventriculomegaly as opposed to 36% of those with additional malformations had chromosomal defects. Furthermore, the degree of ventriculomegaly in the chromosomally abnormal fetuses was relatively mild. In the chromosomally normal fetuses, mild, static ventriculomegaly was associated with apparently normal subsequent mental development.     

First-trimester ductus venosus, nasal bones, and Down syndrome in a high-risk population

OBJECTIVE: Assessing the role of fetal ductus venosus and nasal bones evaluation in first-trimester screening for Down syndrome. METHODS: This was a prospective cohort study in a tertiary referral fetal medicine unit involving 628 consecutive fetuses undergoing chorionic villus sampling. The indication for chorionic villus sampling was an increased risk (more than 1:300) for trisomy 21 based on maternal age and nuchal translucency screening in 313 cases (54.7%), increased maternal age in 195 (34.1%), and other in 64 (11.2%). Immediately before chorionic villus sampling, an ultrasound examination was performed. The pattern of blood flow in the ductus venosus and the presence or absence of the nasal bones was noted. RESULTS: A satisfactory examination of both ductus venosus and nasal bones was possible in 572 fetuses. Of these, 497 (86.9%) had a normal karyotype, and 47 (8.2%) were affected with Down syndrome. The likelihood ratio for trisomy 21 was 7.05 (95% confidence interval 4.27-11.64) in the case of abnormal ductus venosus flow and 6.42 (95% confidence interval 3.86-10.67) in the case of absent nasal bones. CONCLUSION: In addition to increased fetal nuchal translucency, Down syndrome is significantly associated with first-trimester abnormal flow velocity patterns in the ductus venosus and hypoplasia of the nasal bones.     

Prenatally diagnosed fetal lung lesions with associated conotruncal heart defects: is there a genetic association?

Congenital lung malformation can easily be diagnosed by prenatal ultrasound. Associated extrapulmonary malformations such as heart defects and chromosomal aberrations are rare.OBJECTIVE: The objective of this study was to describe the natural history, outcome and other associated malformations in fetuses with lung lesions and an associated heart defect. METHODS: Retrospective analysis of 4 cases of prenatally diagnosed fetal CCAMs and hybrid lesions with an associated heart defect and review of 8 cases in the literature. RESULTS: At a single referral center 1.9% of the fetuses with Congenital cystic adenomatoid malformation (CCAM) were diagnosed with an associated heart defect. Seven of the total 12 cases (58%) reviewed had a conotruncal heart abnormality. Chromosomal abnormalities were found in 5 (42%) of the cases. CONCLUSION: This retrospective review shows that karyotyping in fetal lung lesions with an associated heart defect or isolated large lung lesions is indicated. It also suggests that there is a subpopulation of fetuses with CCAMs who have conotruncal heart defects. This finding may suggest a common genetic background.     

Fetal lateral neck cysts: the significance of associated findings

OBJECTIVES: The detection of fetal lateral neck cysts (FLNC) may create anxiety and confusion among pregnant woman and their physicians. We attempted to determine the incidence and significance of FLNC. Also, we tried to define the importance of the associated findings: the laterality of the finding, triple test results, maternal age and other ultrasonographic findings. METHODS AND MATERIALS: Between January 2000 and September 2003, 80 fetuses were evaluated at our institution for FLNC out of 3350 ultrasonic scans done for fetal malformations at 14-16 weeks' gestation. RESULTS: The incidence of FLNC was 2.4% (80/3350). The majority of cases were isolated (53/80, 66%) and unilateral (46/80, 58%). Down syndrome was associated with nonisolated FLNC. CONCLUSION: Whether the finding was unilateral or bilateral had no significance. Associated increased nuchal translucency (NT) was of importance. Furthermore, the sole finding of increased NT is significant and the finding of the FLNC has no added value. There was no correlation between isolated FLNC without NT and fetal aneuploidy. However, other risk factors increase the risk for aneuploidy by up to 15 fold.     

Ratio of nuchal thickness to humerus length for Down syndrome detection

OBJECTIVE: Ultrasonographic biometry markers are now being used clinically to adjust Down syndrome risk. The limitations are that the definitions of "abnormal" measurements used are arbitrary, thus reducing screening performance, and also that patient-specific Down syndrome risks cannot be calculated. We report a new ultrasonographic algorithm that is sensitive for Down syndrome detection and that estimates individual risk. STUDY DESIGN: Overall in fetal populations with Down syndrome the humerus length is decreased, whereas the nuchal thickness is increased relative to that of a normal population. The nuchal thickness/humerus length ratio therefore shows an even greater increase and magnifies the separation between Down syndrome and healthy groups. Prospective data were collected in midtrimester amniocentesis cases. A regression equation for the median nuchal thickness/humerus length ratio based on biparietal partial diameter was generated. The Down syndrome likelihood ratio, or the odds on the basis of the nuchal thickness/humerus length ratio (multiples of the median), was multiplied by the age-related risk to give the posterior Down syndrome risk. Charts for rapid estimation of individual Down syndrome risk on the basis of maternal age and the nuchal thickness/humerus length ratio were constructed. RESULTS: There were 94 cases of Down syndrome and 4700 cases in which the karyotype was normal. The mean (+/-SD) gestational age of the study population was 16.1 +/- 1.6 weeks. Thirty-three fetuses with Down syndrome and 68 karyotypically normal fetuses had gross anomalies. The equation for the expected median nuchal thickness/humerus length ratio was as follows: 10e(1.7163 - 0.0292) x BPD + 0.0003 x BPD2, where BPD is the biparietal diameter. In the overall study population the nuchal thickness/humerus length ratio and maternal age had a 79.8% detection rate at a 22.1% false-positive rate, compared with maternal age plus humerus length (sensitivity, 55.1%) or maternal age plus nuchal thickness (sensitivity, 66.7%) at the same false-positive rate. For women > or =35 years old the values were 80% and 22.0%, respectively. CONCLUSIONS: We report an ultrasonographic biometry algorithm that, in combination with maternal age, detects 79.6% of Down syndrome cases in a high-risk group. Individual Down syndrome risk can be quickly calculated at the bedside and made available to women who desire this information before making a decision on amniocentesis. On the basis of published standards, ultrasonographic biometry as described would be a cost-effective alternative to amniocentesis in this high-risk group.     

Changing trends in pregnancy outcome among HIV-infected women between 1985 and 1997 in two southern French university hospitals

OBJECTIVE: To determine the utility of the first-trimester fetal nuchal translucency (NT) thickness in the prediction of fetal cardiac malformations. DESIGN: Retrospective study. SETTING: Department of Obstetrics and Gynecology and Medical Genetics, University of Szeged. METHODS: The pre- and postnatal course and outcome, and the relationship between the first-trimester fetal NT thickness and fetal congenital heart defects (CHDs) in 4309 pregnancies ended up with birth or therapeutic abortion between January 1998 and June 2000 were registered. Prenatal care included first- and second-trimester fetal sonography at weeks 10-13 and 18-20, respectively. RESULTS: 4251 births and 58 first- and second-trimester therapeutic abortions due to lethal congenital malformations or chromosomal abnormalities were recorded. Altogether 209 (4.9%) congenital malformations were detected, 39 (18.7%) of which were heart defects with normal karyotype. At birth, 151 congenital malformations were diagnosed, 34 of them were known prenatally. The prevalence of CHDs was 9 per 1000 pregnancies. The measurement of fetal NT thickness was available in 35 of the 39 fetuses with heart defects: it was > or = 3 mm in 18 (51.4%) and <3 mm in 17 (48.6%). A sensitivity of 51.4% was found at a cutoff of 3mm. CONCLUSIONS: An increased NT thickness in chromosomally normal fetuses was found to be highly associated with CHDs and identified in more than half of the affected cases. Furthermore, an increased NT of > or = 3 mm can be regarded a selection criterion for early second-trimester targeted fetal echocardiography and for increased fetal and neonatal surveillance.     

Karyotype and outcome of fetuses diagnosed with cystic hygroma in the first trimester in relation to nuchal translucency thickness

OBJECTIVES: To determine the incidence and to examine the karyotype and the outcome of fetuses diagnosed with cystic hygroma (CH) at 11-14 weeks of gestation. METHODS: The presence of bilateral cystic anechoic cavities in the neck, nuchal translucency (NT), malformations and hydrops was prospectively recorded in 6894 ultrasound examinations in the first trimester, between 2001 and 2004. RESULTS: Forty-two fetuses (0.62%) were diagnosed with CH in the first trimester of pregnancy and 60% of these had an abnormal karyotype. NT was > or = 3 mm in 83% and hydrops was present in 40% of the cases. The karyotype was abnormal in 25 (69%) of these, showing trisomy 18 and 45,XO more often than trisomy 21. NT was <3 mm in seven cases (17%); no hydrops was present and only one had an abnormal karyotype (47 + 18). Eight babies with CH without aneuploidy or hydrops were born alive, seven among them were without malformations and are developing normally at 1 to 18 months of age, the remaining one presented with CHARGE syndrome. CONCLUSIONS: CH is an independent entity from NT and its association with increased NT carries a poor prognosis.     

Re-evaluation of risk for Down syndrome by means of the combined test in pregnant women of 35 years or more

OBJECTIVE: Evaluation of combined test in pregnant women 35 years of age and over to detect fetal Down syndrome. MATERIALS AND METHODS: The study population included 408 pregnant women of 35 years and over, who requested the combined test (nuchal translucency, PAPP-A, free beta hCG, maternal age, cut-off 1:250) before deciding whether to undergo amniocentesis. RESULTS: The test was positive in 66 women who then requested amniocentesis for fetal karyotype determination; the other women had a negative test and declined amniocentesis. False-positives increased with maternal age from 6.6% at 35 years to about 50% at 40 to 41 and 100% in women over 41. Six cases of Down syndrome and two cases of trisomy 18 were detected. Not a single case of Down syndrome or trisomy 18 was missed, and other chromosome abnormalities were detected as well. CONCLUSIONS: The application of the combined test reduced the need for invasive testing to only 14% of the studied pregnant population, without missing any of the fetuses with trisomy 21 or 18.     

Increased nuchal translucency and cystic hygroma in the first trimester: prenatal diagnosis and neonatal outcome

OBJECTIVE: A prospective study of pregnancy outcome in fetuses with increased nuchal translucency above the 95th centile (group NT) or cystic hygroma (group CH) at 10 to 14 weeks of gestation was performed. PATIENTS AND METHODS: Maternal and fetal data (nuchal translucency, caryotype, pregnancy outcome) and infant follow-up of 223 fetuses with first trimester nuchal translucency thickness (183 NT and 40 CH) were analysed. RESULTS: The measurement of nuchal translucency thickness shows a significant difference between group CH and NT (7.4+/-2.9 mm compared 3.7+/-0.8 mm). Chromosomal abnormalities were present in 55% (22/40) in group CH, with 9 cases/22 (40.9%) of Turner syndrome, compared with 14.2% (26/183) in group NT with trisomy 21 in 15 cases/26 (57.7%) (P<0.05). The rate of unfavourable outcome of pregnancy (spontaneous abortion, elective termination of pregnancy, serious structural anomalies) was 80% (32/40) in group CH compared with 18% (33/183) in group NT (P<0.05). In chromosomally normal pregnancies, the rate of fetus with no visible serious structural anomalies was 44.4% (8/18) in group CH compared with 93% (146/157) in group NT (P<0.05). DISCUSSION AND CONCLUSION: Our data show ultrasonographic evaluation of the fetal nuchal translucency thickness at the first trimester is actually indispensable. Neonatal outcome and malformation rate in fetuses with increased nuchal translucency or cystic hygroma are different, even with normal karyotype.     

Early diagnosis of major cardiac defects in chromosomally normal fetuses with increased nuchal translucency.

OBJECTIVE: To determine the value of early ultrasound examination for prenatal diagnosis of cardiac defects in chromosomally normal fetuses with increased nuchal translucency thickness at 10-14 weeks of gestation. DESIGN: Prospective audit. SETTING: Fetal Medicine Centre. METHODS: Specialist fetal echocardiography was carried out in 398 chromosomally normal fetuses with a nuchal translucency measurement above the 99th centile (> or = 3.5 mm). In the first 75 pregnancies the cardiac scan was carried out at 17-22 weeks and the next 323 cases had one scan at 13-17 weeks and another at 20-22 weeks. Pregnancy outcome was obtained in all of the cases. RESULTS: Major cardiac defects were present in 29 (7.3% of 398) cases and in 28 of these the diagnosis was made by antenatal echocardiography. In 27 of the 29 fetuses with major cardiac defects echocardiography was carried out at 13-17 weeks and an abnormality was suspected in 24 of the cases (88%). CONCLUSIONS: Increased nuchal translucency in chromosomally normal fetuses is associated with an increased prevalence of major cardiac defects and, as such, is an indication for specialist fetal echocardiography. Most of the cardiac abnormalities are detectable on antenatal fetal echocardiography and many can be excluded by early scanning.     

Cut-off criteria for second-trimester nuchal skinfold thickness for prenatal detection of Down syndrome in a Thai population.

OBJECTIVE: To evaluate the use of progressive cut-offs for nuchal skinfold thickness with advancing gestational age and the commonly applied cut-off method (> 6 mm) for prenatal detection of Down syndrome in a Thai population. METHOD: A prospective study was performed by experienced perinatologists on 2150 women undergoing second-trimester amniocentesis for the indications of advanced maternal age and past history of chromosomal abnormality. Reference ranges were established for nuchal skinfold thickness from the 16th to the 24th week, using either gestational-specific centiles or the parametric method. Assaying different cut-off criteria for both centile and the parametric methods were calculated and then compared with the commonly applied cut-off level (> or = 6 mm.). RESULTS: There were 2114 chromosomally normal pregnancies, 19 fetuses with Down syndrome (1:113), and 17 other chromosome abnormalities. In fetuses with normal karyotype the nuchal skinfold thickness increased with advancing gestational age [NF (mm) = -0.502 + 0.212 GA (week), r = 0.36, P < 0.001]. The sensitivities of an abnormal nuchal skinfold thickness using different cut-off criteria for detecting Down syndrome were low (5.3-26.3%) with the false positive rates ranging from 2.5 to 16.5%. CONCLUSIONS: In this study, measurement of second-trimester nuchal skinfold thickness was a poor and unreliable screening test for fetal Down syndrome in a Thai population.