First trimester diagnosis of sirenomelia by 2D and 3D ultrasound.

A case of sirenomelia in a 27-year-old woman detected at 11 weeks 5 days of gestation is presented. It was suspected by two-dimensional sonography and color Doppler imaging. Three-dimensional ultrasound confirmed the final diagnosis. With detailed evaluation of the acquired volumes, valuable information was obtained about the anatomical as well as pathological features of the fetus.

Changes in the approach for invasive prenatal diagnosis in 35,127 cases at a single center from 1977 to 2004.

OBJECTIVES: To evaluate the changes in the approaches used for invasive prenatal diagnosis for beta-thalassemia and karyotyping at a single center from 1977 to 2004. METHODS: For beta-thalassemia, in 1977 placentacentesis, in 1982 amniocentesis, in 1983 fetoscopy and cordocentesis, in 1983 trancervical chorionic villi sampling (TC-CVS), in 1984 cardiocentesis, in 1986 transabdominal CVS, and in 2002 preimplantation genetic diagnosis (PGD) were introduced. For karyotyping, in 1977 amniocentesis, in 1983 cordocentesis and cardiocentesis and TC-CVS, in 1986 TA-CVS and in 1991 hepatic vein sampling were introduced. Rates of approaches used were retrospectively considered, for 5 different groups (1977-1981; 1982-1985; 1986-1993; 1994-1999; 2000-2004). RESULTS: 35,127 invasive prenatal diagnoses were considered, and 42 PGD included. For beta-thalassemia 6,547 diagnoses were performed and 42 PGD. Since 1986-1993, TA-CVS was the only approach used except for 42 PGD in the 2000-2004 group. For karyotyping 28,538 diagnoses were performed. Amniocentesis and TA-CVS have been the most frequently used in the last years, while cordocentesis and hepatic vein sampling have shown a decline after their introduction. CONCLUSION: TA-CVS is now the only technique used for beta-thalassemia. For karyotype, amniocentesis and TA-CVS are the most frequently used procedures. Obstetrical and laboratory experience, the availability of screening, and other individual factors, have influenced the choice, towards an earlier approach in pregnancy.

Nuchal translucency and nasal bone for trisomy 21 screening: single center experience.

AIM: To evaluate the feasibility and diagnostic accuracy of fetal nuchal translucency and nasal bone assessment at 11-14 weeks for screening of trisomy 21 at a single center. METHODS: Nuchal translucency measurement and nasal bone evaluation in relation to the fetal karyotype for singleton fetuses were retrospectively assessed at the Ospedale Microcitemico, Cagliari, Italy, in a three-year period (2001-2004). Nuchal translucency was considered enlarged if greater than or equal to the 95th centile for crown-rump length (CRL) of the reference ranges, and nasal bone was described as present or absent during the evaluation of the fetal facial profile. Sensitivity and specificity for trisomy 21 were assessed for nuchal translucency and absent nasal bone. RESULTS: Among 32,000 cases recorded in the database including fetuses from 11 to 14 weeks, 16,654 fetuses were included in the study with both nuchal translucency measurement and nasal bone evaluation. Median maternal age was 32 years (range, 14-49). In 854 fetuses (5.1%), nuchal translucency was greater than the 95th centile, and 744 (87.1%) of them had a normal karyotype. Among 141 (0.8%) diagnosed cases of chromosomopathies, there were 96 cases of trisomy 21. Nuchal translucency was enlarged in 110 chromosomopathies and in 72 trisomies 21. Sensitivity was 75.0% (95% confidence interval [CI], 65.5-82.6), and specificity 95.5% (95% CI, 95.2-95.8). In fetuses with enlarged nuchal translucency and normal karyotype, there were 30 structural defects (4%), and among these, 15 heart defects (2%). Measurement of nuchal translucency was possible in all cases where it was attempted. In 13 cases (0.1%), it was not possible to determine the visibility of the nasal bone. In 16,486 cases, the nasal bone was defined as visible and in 155 cases (0.9%) the nasal bone was described as absent. The nasal bone was absent in 56 trisomies 21 and in 23 other chromosomopathies, as well as in 76 normal karyotype fetuses. The sensitivity was 58.3% (95% CI, 48.3-67.7) and specificity 99.5% (95% CI, 99.4-99.6). The sensitivity of enlarged nuchal translucency and nasal bone was 80.2% (95% CI, 71.1-86.9). CONCLUSIONS: Enlarged nuchal translucency and absent nasal bone are useful markers of trisomy 21 in the first trimester ultrasound screening, increasing the sensitivity of detection of affected fetuses.

Nuchal translucency measurement at different crown-rump lengths along the 10- to 14-week period for Down syndrome screening.

OBJECTIVES: To evaluate the screening accuracy for Down syndrome of nuchal translucency (NT) measurement at different crown-rump length (CRL) subgroups along the 10- to 14-week period. METHODS: NT was classified 'enlarged' if greater than or equal to 1.5 and 2.0 multiples of the regressed median. Accuracies for Down syndrome (formula=[(TP + TN)/(TP + TN + FP + FN)]x100, where TP: true positive, TN: true negative, FP: false positive, FN: false negative) were evaluated in four classes of CRL: 38-44 mm, 45-54 mm, 55-70 mm, and 71-84 mm, and compared. RESULTS: Of 20 743 fetuses, 20 611 were with no chromosomal abnormalities and 132 were with Down syndrome. Down syndrome fetuses with enlarged NT were 99 (greater than or equal to 1.5 MoM) and 86 (greater than or equal to 2.0 MoM). Sensitivity decreased with gestation, while specificity increased, resulting in increasing likelihood ratios with gestation for each of the CRL groups (8.1, 14.1, 16.3, 17.1 with the use of the 1.5 MoM cut-off, and 13.2, 27.1, 50.1, 84.1 for the 2.0 MoM cut-off). The accuracy increased with gestation (89%, 95%, 95%, 96% with the use of the 1.5 MoM cut-off, and 94%, 97%, 98%, 99% for the 2.0 MoM cut-off, for each of the CRL groups), differences being statistically significant between periods in half of the comparisons. CONCLUSIONS: Although sensitivity of NT assessment for Down syndrome screening decreased as gestation advanced from the 10th to the 14th week, accuracy showed a remarkable increase. These changes should be taken into account in defining and improving the Down syndrome screening policies.

Changes in nuchal translucency thickness in normal and abnormal karyotype fetuses.

OBJECTIVE: To investigate the dynamic trend of the nuchal translucency thickness between fetuses with normal and abnormal karyotype. DESIGN: Prospective observational study. SETTING: Ospedale Microcitemico, Cagliari, Italy. POPULATION: A cohort of 305 first trimester fetuses. METHODS: Fetuses with a nuchal translucency greater than or equal to the 95th centile were invited for a second nuchal translucency measurement. The finding of an 'increased or unchanged' or 'diminished' thickness was compared in fetuses with normal and abnormal karyotype. MAIN OUTCOME MEASURES: Nuchal translucency and karyotype. Median maternal age was 35 years (min 17, max 44) and median crown-rump length at first visit was 50 mm (min 38, max 80). A second nuchal translucency measurement was carried out in 292 fetuses, resulting in increased or unchanged values in 95 cases and decreased nuchal translucency in 197 cases. Two hundred and twenty-six (77.4%) fetuses had normal karyotype and 66 (22.6%) had abnormal karyotype (44 trisomies 21, 10 trisomies 18, 5 trisomies 13, 4 cases of 45 X0, 1 case of 47,XXY, 1 case of 47,XXX and 1 translocation). In the 66 chromosomally abnormal fetuses, the second nuchal translucency measurement was enlarged or unchanged in 37 (56%), and diminished in 29 (44%), while in the 226 normal fetuses the second nuchal translucency measurement was enlarged or unchanged in 58 cases (25%) and diminished in 168 (75%) (relative risk 2.6, 95% confidence interval 1.7-4.0). CONCLUSION: In fetuses with abnormal karyotype, the second nuchal translucency measurement tends to be increased or unchanged, while in normal cases the size of nuchal translucency is generally reduced.

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.