C. G. V. Murta

Medida da Translucência Nucal no Rastreamento de Anomalias Cromossômicas

Purpose: to study the value of nuchal translucency (NT) measurement in the screening for chromosomal abnormalities at 10-14 weeks of gestation. Methods: a total of 1152 fetuses were studied consecutively. In 124 cases a cytogenetic study was performed on material obtained from a biopsy of the chorionic villus, and in 1028 cases the result was based on the postnatal phenotype. In addition to the routine ultrasonographic examination, all fetuses were submitted to measurement of the NT thickness. For statistical analysis Students t test and ANOVA were used. Sensitivity, specificity, positive and negative predictive values, false-positive rate and likelihood ratio were calculated. Results: twenty-three cases of chromosomal abnormalities occurred. Of these abnormal cases, NT measurement was above the 95th percentile in 16 (sensitivity of 69.5%). In the group of normal fetuses (1129 cases), NT measurement was above the 95th percentile in 41 (specificity of 96.3%, positive and negative predictive values of 28.0% and 99.3%, respectively, false-positive rate of 3.7% and likelihood ratio of 19.1). Conclusion: our results suggest that the presence of chromosomal abnormalities may be strongly suspected when there is an increased NT thickness. One can infer that the quantitative NT analysis is sufficient to classify the risk of chromosomal anomalies in the first trimester of the pregnancy. Although the ultrasound operators training and skill is still necessary, it is a method of clinical applicability.

Valor preditivo do resultado fetal da dopplervelocimetria de ducto venoso entre a 11ª e a 14ª semanas de gestação

PURPOSE: to study the value of Doppler velocimetry of the ductus venosus, between the 11th and 14th weeks of pregnancy, associated to the nuchal translucency thickness measurement, in the detection of adverse fetal outcome. METHODS: a transversal and prospective study in which a total of 1,268 fetuses were studied consecutively. In 56 cases, a cytogenetic study was performed on material obtained from a biopsy of the chorionic villus and, in 1,181 cases, the postnatal phenotype was used as a basis for the result. In addition to the routine ultrasonographic examination, all the fetuses were submitted to measurement of the nuchal translucency thickness and to Doppler velocimetry of the ductus venosus. Aiming at prevalence and accuracy indices, sensitivity, specificity, positive predictive value, negative predictive value, probability of false-positive, probability of false-negative, reason of positive probability and reason of negative probability were calculated and analyzed. RESULTS: from the total of 1,268 fetuses, 1,183 cases were selected for analysis. From this number, 1,170 fetuses were normal (98.9%) and 13 fetuses presented adverse outcome at birth (1.1%), including fetal death (trisomy 21 and 22) in two cases; genetic syndrome (Nooman) in one case; two cases of polymalformed fetuses; cardiopathy in three cases; and other structural defects in five cases. The prevalence of the modified ductus venosus (wave A zero/reverse) in the studied population was of 14 cases (1.2%), with a false-positive rate of 0.7%. CONCLUSIONS: there is a significant correlation between the alteration of the ductus venosus Doppler velocimetry and the thickness of the nuchal translucency as an ultrasonographic marker for the first trimester of gestation, in the detection of adverse fetal outcome, especially serious malformations. The ductus venosus was able to diminish the false-positive result in comparison to the isolated use of the nuchal translucency thickness, improving considerably the positive predictive value of the test.

Ultra-sonografia tridimensional do colo uterino na gestação: perspectivas

The measurement of cervical length utilizing transvaginal ultrasound is of help for pregnant women screening for premature labor, the shortening of the cervix being a predictor of higher risk of preterm delivery. Traditional methods for evaluating the uterine cervix during pregnancy are limited and unsatisfactory. Digital examination of cervix, considered as the standard method, demonstrates large variation among different examiners; on the other hand, transvaginal sonography is an effective method of examination during pregnancy. Recently, three-dimensional ultrasound has been used in the clinical practice including the study of uterine cervix. The three-dimensional technology allows acquisition and storage of a large volume of data. Such stored information can be reformatted and analyzed through an unlimited number of planes. The three-dimensional transvaginal ultrasound is the unique imaging method capable of obtaining a true coronal plane by direct correlation of the views in a multiplanar display. This method seems to offer a diagnostic potential because of the cervical ultrasonography increased accuracy.

P02.32: Spinal muscular atrophy and increased nuchal translucency—case report

congenital contractural syndrome type 2 (LCCS2) (OMIM 607598) which is also associated with renal and cardiac malformations. A genome-wide linkage analysis, demonstrating linkage to approximately 6 cM homozygosity region on chromosome 12q13 between markers D12S1604 and D12S83, was found. Therefore, early genetic detection of this syndrome is possible. However, many patients known to be carriers of this genes deny an invasive procedure and in others this genetic diagnosis is not found. Thus, sonographic detection may be the sole tool for early detection of this abnormality. The sonographic appearance of LCCS2 in our area may appear late in second trimester and early sonographic diagnosis may be important in counseling these patients, Lately, we have sonographically diagnosed 3 patients in the fetal malformation clinic at 13–14 weeks gestation. The main sonographic symptom was myoclonic jerks of hands and feet of these fetuses. Hands were flexed in the elbow joints and the jerks were from the shoulder girdle. Jerks were from the hip joint. At that time no joint contractures were apparent. These appeared only at 17 weeks gestation. In summary, tonic myoclonic jerks are demonstrated sonographically and can be an early neurologic sign for hypokynesia/akinesia syndrome. Future sonographic observations in first trimester should be offerred to high risk patients prone to neurological accidents and congenital malformations.

P25.01: The role of fetal nuchal translucency and ductus venosus Doppler at 11–14 weeks of gestation in the detection of Down syndrome

Objective: To determine whether Doppler velocimetry of the ductus venosus can improve the predictive capacity of increased nuchal translucency in the detection of trisomy 21 at 11–14 weeks of gestation. Methods: Ductus venosus Doppler ultrasound blood velocity waveforms were obtained prospectively at 11–14 weeks of gestation in 2280 consecutive singleton pregnancies. Waveforms were classified either as normal in the presence of a positive A-wave, or as abnormal if the A-wave was absent or negative. All cases were screened for chromosomal defects by a combination of maternal age and fetal nuchal translucency thickness. Concerm TN, a Down sindromy was suspected when the nuchal translucency was above the 95th centile. In 344 cases karyotyping was performed. Results: Down syndrome was found in 37 cases. On basis in the NT the overall detection rate, specificity, positive predictive value, negative predictive value and likelihood ratio for trisomy 21 were 85.7%, 97.1%, 99.9%, 28% and 44.9% respectively. On basis in the ductus venosus blood flow during atrial contraction the sensitivity, specificity, the negative and positive predictive values and likelihood ratio were 82.9%, 98.8%, 99.7%, 56.9%, 69% respectively. Conclusions: Enlarged nuchal translucency and abnormal ductus venosus blood flow are useful markers of trisomy 21 in the first trimester ultrasound screening, assessment of ductus venosus blood flow velocimetry could improve the predictive for the detection of Down syndrome.

Correlação da área do cordão umbilical com parâmetros antropométricos em gestações normais

OBJECTIVE: To develop a nomogram for the umbilical cord cross-sectional area (UCCSA) in normal pregnancies in women between 20 to 40 weeks gestation. MATERIALS AND METHODS: A cross-sectional study was developed to determine reference ranges for the UCCSA during normal pregnancies (patients with known dates of last menstrual period, and a normal ultrasound examination before the 20th week of gestation). The measurements of the UCCSA were obtained using a plane adjacent to the insertion of the cord in the abdomen. A 3.5 MHz transabdominal transducer was used on all ultrasound equipment utilized (a Synergy Multi Sync M500, a Toshiba 140 and a Toshiba Corevision). The statistical analysis was performed using the SPSS (Statistical Package for Social Sciences) software. RESULTS: The Kolmogorov-Smirnov test showed a normal distribution of the data and the nomogram was constructed by linear regression. The analysis of variance (F test = 356.27) showed that our model was significant at a p < 0.01 level, and therefore represented adequately the studied population. The confidence interval (95%) contained the real value of the UCCSA. The equation constructed for the UCCSA (y) according to the gestational age (x) was: y = -532.27 + 44.358x - 0,655x². CONCLUSION: The nomogram developed for the UCCSA shows a progressive increase of the UCCSA up to the 32nd week, stabilization until the 34th week, and decrease after the 35th week of gestation.

P04.09: Why absent flow during the atrial contraction of the ductus venosus Doppler must be considered as a positive marker of Down syndrome?

Objectives: To determine whether absent flow during atrial contraction in the Doppler velocimetry of the ductus venosus can improve the predictive capacity of this method in the detection of Down syndrome at 11–14 weeks of gestation. Methods: Ductus venosus Doppler ultrasound blood velocity waveforms were obtained prospectively at 11–14 weeks of gestation in 2495 consecutive singleton pregnancies. In the first group waveforms were classified either as normal in the presence of a positive A-wave, or as abnormal if the A-wave was absent or negative. In the second group, waveforms were classified as abnormal if only A-wave was negative (reverse flow). All cases were screened for chromosomal defects by a combination of maternal age and fetal nuchal translucency thickness. Results: Down syndrome was found in 39 cases. In the first group the flow was abnormal in 30 cases, the overall detection rate, specificity, positive predictive value, negative predictive value and likelihood ratio for trissomy 21 were 76.9%, 99.0%, 54.5%, 99.6% and 75.5 respectively. On basis in the ductus venosus blood flow during atrial contraction as positive marker only A-wave was negative (24 cases) the sensitivity, specificity, the positive and negative predictive values and likelihood ratio were 61.5%, 99.1%, 53.3%, 99.4%, 71.9 respectively. Conclusions: Abnormal ductus venosus blood flow is an useful marker of Down syndrome in the first trimester ultrasound screening. We could improve the predictive for the detection of trisomy 21, and consequently becoming an excellent marker, by considering absent flow during atrial contraction as a positive marker (abnormal). Screening for Down syndrome in Brazil presents comparable results to those in other countries. It is a method of clinical applicability in any part of the world.

P17.14: Absent flow during the atrial contraction in the ductus venosus Doppler: normal or abnormal?

Objectives: The aim was evaluated the preliminary results of an implementation of assessment of risk in a tertiary center hospital in Brazil. Methods: This was a prospective study of 1.555 singleton pregnancies with a live fetus at 10–14 weeks of gestation attending for routine antenatal care in a tertiary hospital in Brazil. Fetal crown–rump length (CRL) and NT thickness were measured and the risks for trisomy 21 were calculated by a combination of maternal age and fetal NT according to the software provided by The Fetal Medicine Foundation. Results: The maternal age ranged from 13 to 48 years (median, 30 years, SD +7.6) whereas 15.5% were younger than 20 years (144/931), 32.0% and 7.4% older than 35 years (506/1555) and 40 years old. The body mass index was greater than 30 kg/m2 in 10% of these pregnant women and 61% from 18.5–24.9 kg/m2. Nulliparous and primiparous were found in 48.9% and 29.8% respectively. The distribution of NT measurements revealed that 64.5% and 11.6% of the population had measurements above the 50th and 95th percentile for gestational age with no difference among the six members of the group. The estimated risk was greater than 1 : 300 and 1 : 100 in 57 patients (3.7%) and in 16 patients (1.0%) respectively. Based on the distribution of maternal age, it was expected 2.6 cases of trisomy 21 and approximately the same number of other chromosomal defects. In this population, the invasive procedure was performed in 100 pregnant women and there were three cases of autosomal trisomies, one of trisomy of sex chromosomes, one case of Turner syndrome and two cases of structural chromosomal alterations. Of this population, 85.7% (6/7) had NT > 95th percentile for gestational age and 42.8% (4/7) were younger than 35 years old. Conclusions: The discriminative capacity of nuchal translucency measurement makes it a useful tool in screening for chromosomal abnormalities.

P30.16: Hipercoiling of the umbilical cord associated with the fetal death

Introduction: Hipercoiling of the umbilical cord and fetal-placental thrombotic vasculopathy are well know conditions but sometimes undervalued as a cause of adverse perinatal outcome. Like about several other placental lesions, the difficulty arise in the lack of routine practice of always correlate the clinical and ultrasound findings with the placental pathology, as illustrated in this case. Case report: A caucasian, 38 years old, primiparous and married patient, residing at Vitoria, Espı́rito Santo Sate, Brazil. In December 2008 showed positive beta-HCG and initiated prenatal care; the labor was scheduled to 06/08/09. During pregnancy, did followup clinical, laboratory and routine ultrasound, without maternal or fetal abnormality. However, on 17/07/09, with 36 weeks of gestation, a routine ultrasound revelead fetal death. The delivery occurred at the same day. At autopsy, it was found that fetal death occurred 12 to 24 hours before termination, and the findings were diagnostics of fetal growth restriction (fetal weight of 2027 g, z/IG: −1.9, and the liver, kidney and thymus was of reduced in size), long (720 mm, z/IG: 3.9) and hipercoiling cord (UCI: 0.56, VR 0.10 A 0.30), diffuse villous immaturity, extensive alantochorial and chorial thrombosis, hemorrhagic endovasculopathy and Altshuler stage 2, grade 1 chorioamnionitis, involving extra-placental membranes and placenta. Comments: This case stands out, curiously, by the contrast between the absence of detectable clinical and ultrasonographic manifestations and the exuberance of pathological lesions. We recommend that the umbilical cord coil index become part of the routine fetal anatomic survey in the second trimester ultrasonography.

P31.11: Nuchal translucency and ductus venosus Doppler for trisomy 21 screening: which one is the best?

trisomy 21. In the remaining three cases with outcomes of trisomy 21, the diagnosis of trisomy 21 was not made in the first trimester although sonographic findings on the second-trimester ultrasound led to the prenatal diagnosis in two of the cases (atrioventricular canal in one and flat face with hypoplastic NB in the other). Conclusion: NB assessment can increase the detection rate of trisomy 21 by detecting the subset of trisomy 21 fetuses presenting with normal NT. Teaching and training in ultrasound assessment of the NB is important for establishing the real value of this ultrasound marker in the population of trisomy 21 fetuses with normal nuchal translucency thickness.