Should cell-free DNA testing be used in pregnancy with increased fetal nuchal translucency?

OBJECTIVE: To assess the frequency of atypical chromosomal and submicroscopic anomalies, as well as fetal structural abnormalities, observed on first-trimester ultrasound scan in fetuses with nuchal translucency (NT) thickness > 99th centile, in order to evaluate the suitability of using standard cell-free DNA (cfDNA) testing as the sole screening test in these pregnancies. METHODS: This was a retrospective cohort study of 226 fetuses with NT > 99th centile at 11-14 weeks' gestation, between January 2013 and December 2017, in a clinical setting in which greater than 95% of pregnant women receive first-trimester combined screening. All patients underwent genetic testing by means of quantitative fluorescence polymerase chain reaction and chromosomal microarray analysis, mainly in chorionic villus samples. We assessed the theoretical yield of two cfDNA testing models, targeted cfDNA (chromosomes 21, 18 and 13) and extended cfDNA (chromosomes 21, 18, 13 and sex chromosomes), and compared it with that of cytogenetic testing and ultrasound assessment in the first and second or third trimesters. RESULTS: In the 226 fetuses analyzed, cytogenetic testing revealed 84 (37%) anomalies, including 68 typical aneuploidies (involving chromosomes 13, 18 or 21), six sex chromosome aneuploidies (four cases of monosomy X and two of trisomy X), three clinically relevant atypical chromosomal anomalies (one trisomy 22, one trisomy 21 mosaicism and one unbalanced translocation), five submicroscopic pathogenic variants and two cases with Noonan syndrome. Targeted and extended cfDNA testing would miss at least 12% (10/84) and 19% (16/84), respectively, of genetic anomalies, accounting for 4.4% and 7.1% of the fetuses with an increased NT, respectively. Finally, of the 142 fetuses with no identified genetic anomaly, a major fetal malformation was observed in 15 (10.6%) fetuses at the early anomaly scan, and in 19 (13.4%) in the second or third trimester. CONCLUSIONS: cfDNA does not appear to be the appropriate genetic test in fetuses with NT > 99th centile, given that it would miss 12-19% of genetic anomalies in this group. Additionally, first-trimester ultrasound will identify a major structural abnormality in 11% of the fetuses with NT > 99th centile and no genetic anomaly. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Further insights into diastolic dysfunction in first-trimester trisomy-21 fetuses.

OBJECTIVE: To assess fetal cardiac function in first-trimester trisomy-21 fetuses as compared with fetuses with other aneuploidies, euploid fetuses with cardiac defects or isolated increased nuchal translucency (NT) and controls. METHODS: During a 2.5-year period, NT, ductus venosus (DV) blood flow, diastolic filling time, early filling time, tricuspid flow, tricuspid and mitral valve E/A velocity ratios, left ventricle shortening fraction, left myocardial performance index and fetal heart rate were assessed in fetuses with a crown-rump length between 45 and 84 mm undergoing chorionic villus sampling at our center. Cardiac parameters among study groups were compared with the use of 95% CIs. RESULTS: The study population comprised 28 fetuses with trisomy 21, 25 with other aneuploidies, 94 euploid fetuses with abnormal findings (27 with cardiac defects, 31 with other structural anomalies and 36 with isolated increased NT) and 271 controls. Trisomy-21 fetuses showed signs of diastolic dysfunction such as increased DV pulsatility index and E/A ratios together with a higher prevalence of tricuspid regurgitation. However, no differences were found in euploid fetuses with cardiac defects or isolated increased NT. CONCLUSIONS: No signs of cardiac dysfunction were observed in euploid fetuses with increased NT or cardiac defects, while in trisomy-21 fetuses signs of diastolic dysfunction could be potentially attributed to volume overload.

Is nuchal translucency a useful aneuploidy marker in fetuses with crown-rump length of 28-44 mm?

OBJECTIVE: To investigate whether increased nuchal translucency (NT) in fetuses with a crown-rump length (CRL) below 45 mm needs to be re-evaluated at a later stage, or whether the early NT measurement can be used effectively as an aneuploidy marker. METHODS: This was a prospective cohort study including all singleton fetuses with a CRL between 28 and 44 mm, scanned in our center during 2002-2012. The CRL, NT, fetal karyotype (when available) and pregnancy outcome were recorded. NT reference ranges were constructed using the Lambda-Mu-Sigma (LMS) method in non-referred pregnancies after exclusion of chromosomal anomalies. The 95(th) percentile was used to calculate detection rates for chromosomally abnormal fetuses. RESULTS: NT was successfully measured in 643 of 672 fetuses with a CRL of 28-44 mm. Subsequent cytogenetic analysis revealed 11 cases of trisomy 21, 14 cases of trisomy 13 or 18, three cases of monosomy X, three sex trisomies, three triploidies and 12 balanced anomalies. NT was above the 95(th) percentile in 64% of the fetuses with trisomy 21, in 71% with trisomy 13 or 18 and in all three cases of monosomy X. CONCLUSION: NT appears to be useful as a marker for the early detection of fetal trisomies at 9-10 weeks' gestation (28-44 mm CRL).

First-trimester detection of major cardiac defects with the use of ductus venosus blood flow.

OBJECTIVE: To assess the best method of combining fetal nuchal translucency (NT) and ductus venosus (DV) blood flow measurements in the detection of major cardiac defects in chromosomally normal fetuses during the first-trimester scan. METHODS: During an 8-year period NT and DV blood flow were routinely assessed at 11-14 weeks' gestation. Only chromosomally normal singleton pregnancies were included in the study. When a cardiac defect was suspected, or when increased fetal NT and/or absent or reversed (AR) A-wave in the DV was observed, early fetal echocardiography was offered. Data on routine second- and third-trimester scans, neonatal follow-up or postmortem examination were obtained from hospital records. The detection and false-positive rates for all major cardiac defects were calculated for several screening strategies, including: NT or DV pulsatility index for veins (DV-PIV) above a fixed normal centile; AR A-wave; risk based on NT and DV-PIV or A-wave velocity above a fixed normal centile; and combinations of these strategies. RESULTS: The study population included 37 chromosomally normal fetuses with a major cardiac defect and 12 799 unaffected pregnancies. Fetal NT above the 95(th) or the 99(th) centile and AR A-wave was observed in 40, 27 and 39% of the fetuses with major cardiac defects, respectively. A 47% detection rate with a 2.7% false-positive rate was obtained when AR A-wave or NT above the 99(th) centile was used as the selection criterion. CONCLUSIONS: Half of major fetal cardiac defects could be detected in the first trimester if NT and DV Doppler are used to select 2.7% of the general pregnant population for extended fetal echocardiography.

First-trimester detection of structural abnormalities and the role of aneuploidy markers.

OBJECTIVES: To determine the sensitivity of first-trimester ultrasound for diagnosing different structural anomalies in chromosomally normal pregnancies, and to establish the role of aneuploidy markers in the detection of abnormalities. METHODS: This was a retrospective study of chromosomally normal singleton pregnancies with an 11-14-week scan performed in our center during 2002-2009. The ultrasound examination included an early fetal anatomy survey and assessment of nuchal translucency, ductus venosus blood flow and nasal bone. RESULTS: Among 13 723 scanned first-trimester pregnancies with no genetic anomalies and complete follow-up, 439 fetuses (3.2%) were found to present with structural anomalies (194 with major anomalies and 245 with only minor anomalies). Forty-nine per cent of major structural anomalies were detected during the first-trimester scan, the highest rates corresponding to acrania (17/17), holoprosencephaly (three of three), hypoplastic left heart syndrome (10/10), omphalocele (six of six), megacystis (seven of eight) and hydrops (eight of nine). Higher than expected detection rates were obtained for skeletal (69%) and cardiac (57%) defects, coincidentally showing the highest presence of an increased nuchal translucency or abnormal ductus venosus blood flow (38% and 52%, respectively). The finding of an absent nasal bone did not appear to be associated with structural defects. CONCLUSION: About half of major structural abnormalities can be diagnosed in the first trimester. Increased nuchal translucency or abnormal ductus venosus blood flow appear to be associated with cardiac and skeletal defects and may facilitate early detection.

Contingent screening for Down syndrome completed in the first trimester: a multicenter study.

OBJECTIVE: To assess a new contingent screening strategy for Down syndrome completed in the first trimester. METHODS: First-trimester screening combining nuchal translucency thickness measurement and assessment of serum analytes (combined test) was offered to pregnant women who presented for prenatal care during the first trimester to nine health centers and community hospitals in the area served by the Catalan Public Health Service. If an intermediate risk (1/101-1/1000) for Down syndrome was identified, women were referred to the Hospital Clinic Barcelona for risk reassessment that included the use of secondary ultrasound markers (nasal bone, ductus venosus blood flow and tricuspid flow). Intermediate-risk women were divided into two subgroups for further analysis: high-intermediate risk (1/101-1/250) and low-intermediate risk (1/251-1/1000). We compared feasibility and efficacy of both combined and contingent screening strategies. RESULTS: The combined test, the first screening stage, was performed in 16 001 pregnant women, of whom 1617 (10.1%) were found to have an intermediate risk. Further division of this group showed that 1.8% (n = 289) of women were at high-intermediate risk and 8.3% (n = 1328) at low-intermediate risk. The contingent screening strategy significantly reduced the false-positive rate, from 3.0% to 1.3-1.8% (P < 0.001), without affecting the detection rate (which was 75-79% and 76%, with and without the contingent screening strategy, respectively). However, only 45% of intermediate-risk patients underwent the second screening step due to a preference among high-intermediate-risk (1/101-1/250) women for invasive testing and to low uptake among low-intermediate-risk (1/251-1/1000) women. CONCLUSIONS: The proposed first-trimester contingent strategy reduces the screen false-positive rate without impacting on the detection rate of Down syndrome. The low compliance observed in our study may prevent its use in certain populations.

Ductus venosus pulsatility index as an antenatal screening marker for Down's syndrome: use with the Combined and Integrated tests.

OBJECTIVES: To assess the value of ductus venosus blood flow (expressed as pulsatility index, DVPI) in antenatal Down's syndrome screening when used with the Combined and Integrated tests. METHODS: DVPI measurements between 10 and 13 weeks' gestation in 66 Down's syndrome and 7184 unaffected pregnancies were collected from women attending the Hospital Clinic, Barcelona, for antenatal care from 1999 to 2007 and combined with the Serum Urine and Ultrasound Screening Study (SURUSS) data to model screening performance, safety and cost-effectiveness of the screening tests with and without DVPI. RESULTS: The median DVPI multiple of the normal median in Down's syndrome pregnancies was 1.55 (95% CI 1.36-1.73). As a single screening marker without using maternal age, DVPI has a 62% detection rate for a 5% false-positive rate. At a 90% detection rate (first trimester measurements at 11 weeks' gestation) the addition of DVPI reduced the false-positive rate of the Combined test from 8.5% to 4.6% and the Integrated test from 2.0% to 1.1%, with a corresponding reduction in fetal losses from diagnostic procedures. There was no material loss of cost-effectiveness. CONCLUSION: Addition of DVPI measurements to the Combined and Integrated tests substantially improves the efficacy and safety of antenatal Down's syndrome screening.

Combining fetal nuchal fold thickness with second-trimester biochemistry to screen for trisomy 21.

OBJECTIVE: To assess second-trimester screening for trisomy 21 by combining ultrasound nuchal fold (NF) measurement with maternal serum biochemistry. METHODS: NF, maternal serum alpha-fetoprotein (AFP) and free beta-human chorionic gonadotropin (beta-hCG) were determined concurrently at 14-19 weeks' gestation in a study population comprising 1813 women with singleton pregnancies, including 1257 unselected women undergoing serum screening for trisomy 21 (1999-2002), and 556 high-risk pregnancies prior to amniocentesis (2003-2005), 402 of whom had positive serum screening tests. The results were expressed in multiples of the gestation-specific normal median (MoMs). RESULTS: There were 1799 unaffected singleton pregnancies, and their NF values approximately fitted a log Gaussian distribution over a wide range. There was a weak but statistically significant correlation between log NF and log AFP (r = - 0.069, P < 0.005) and the correlation coefficient between log NF and log free beta-hCG was even smaller and not statistically significant (r = 0.038, P = 0.11). Among the seven trisomy 21 pregnancies, the median NF level was 1.53 MoM (geometric mean 1.75 MoM), a highly statistically significant increase compared with unaffected pregnancies (P < 0.0001, one-tail Wilcoxon Rank Sum Test). In pregnancies referred because of positive serum screening tests (391 unaffected, seven cases of trisomy 21, one of monosomy X and three other chromosomal anomalies) the use of NF to modify the serum screening risk would have reduced the invasive procedures in unaffected pregnancies by 46% without affecting the detection rate of trisomy 21 or other anomalies. Statistical modeling predicted that adding NF to AFP and free beta-hCG would increase detection more than would adding unconjugated estriol as well as inhibin-A, an analyte that is difficult to measure with precision. CONCLUSIONS: The addition of NF measurement to second-trimester biochemical markers improves screening performance, and could overcome drawbacks in the implementation of inhibin-A assay in clinical practice.

Uterine artery Doppler at 11-14 weeks of gestation to screen for hypertensive disorders and associated complications in an unselected population.

OBJECTIVES: To establish reference values for the first-trimester uterine artery (UtA) pulsatility index (PI) and to investigate the role of UtA Doppler in the early prediction of hypertensive disorders and their associated complications in an unselected Mediterranean population. METHODS: A prospective study including 1091 consecutive singleton pregnancies undergoing routine early ultrasound screening at 11-14 weeks of gestation was performed. The left and right UtA were examined by color and pulsed Doppler transvaginally. The mean PI and the presence of bilateral protodiastolic notching were cross-sectionally recorded. Reference ranges were calculated and the pregnancies were followed for occurrence of pre-eclampsia, gestational hypertension, intrauterine growth restriction, placental abruption and stillbirth. The sensitivity and predictive values of a mean UtA-PI>95th percentile and the presence of bilateral notching in the prediction of these pregnancy complications were calculated. RESULTS: A total of 999 women were finally included. Both the mean UtA-PI and the prevalence of bilateral notches showed a significant linear decrease between 11 and 14 weeks' gestation. Sixty-seven (6.7%) pregnancies developed at least one of the formerly described complications, including 22 (2.2%) cases of pre-eclampsia and 37 (3.7%) cases with intrauterine growth restriction. Compared with women with a normal outcome, complicated pregnancies showed a significantly higher mean PI (2.04 vs. 1.75; P<0.05, t-test) and a higher prevalence of bilateral notching (58% vs. 41%; P<0.05, Chi-square test). Using the 95th percentile in mean UtA-PI as a cut-off, 23.9% (95% CI, 13.7-34.1) of complicated pregnancies and 30.8% (95% CI, 5.68-55.85) of severe cases were identified. CONCLUSIONS: Our results suggest that pregnancies with an increased risk of developing hypertensive disorders and related complications already have an abnormally increased UtA-PI in early pregnancy. However, the use of a single uterine Doppler measurement for screening purposes in unselected early pregnancy populations has limited clinical value. The use of UtA-PI combined with other screening tests needs to be determined by further investigation.

Transfusión intravascular fetal en el tratamiento de la isoinmunización / Fetal intravascular transfusión in the treatment of alloimmunization

Objetivo: Evaluar los resultados de la transfusión fetal intravascular en el tratamiento de la isoinmunización, durante el período 1990-2003. Sujetos y métodos: Se ofreció una cordocentesis para realizar un hemograma fetal a las gestantes isoinmunizadas con sospecha de anemia fetal significativa. Se practicó transfusión intrauterina cuando el valor del hematocrito fetal fue inferior a -2 desviaciones estándar para la edad gestacional. Las transfusiones se repitieron aproximadamente cada 3 semanas hasta la semana 34-35. Resultados: Se practicó una cordocentesis en 32 gestaciones, en 11 (34%) de las cuales no se objetivó una anemia fetal significativa de acuerdo con los criterios establecidos. En 19 gestaciones se realizaron un total de 50 transfusiones entre las 21 y 35 semanas. No se observó ninguna pérdida fetal espontánea. A los 0-13 años de vida, todos los niños presentan una evolución correcta para su edad. Conclusión: La transfusión intravascular fetal es una técnica efectiva en el tratamiento prenatal de la anemia fetal con resultados favorables a largo plazo

Objective: To assess perinatal outcome after fetal intravascular transfusion in the treatment of alloimmunization between 1990 and 2003. Subjects and methods: Fetal blood sampling was offered to immunized pregnant women when significant fetal anemia was suspected. Intravascular fetal transfusion was performed when the fetal hematocrit was below -2 standard deviations for gestational age. Serial transfusions were scheduled every 3 weeks until approximately 34-35 weeks. Results: Cordocentesis was performed in 32 singleton pregnancies. In 11 (34%) of these, no fetal anemia as defined by the established criteria was detected. Fifty intravascular fetal transfusions were performed in 19 pregnancies, from the 21st to the 35th week. No spontaneous fetal losses were observed. At 0-13 years of age, all the children showed normal development for their age. Conclusion: Fetal intravascular transfusion is an effective procedure in the prenatal treatment of fetal anemia with favorable long-term outcome

Prevalence of anti-Legionella pneumophila antibodies in various groups with different risk factors in Seville (Spain).

A study was undertaken to establish the background prevalence of antibodies to L. pneumophila in 324 persons from the area of Seville, Spain. The serum specimens were obtained from healthy volunteers divided into groups with different risk factors. The results were as follows: a prevalence of 1.96% in 51 persons working in a cooling-tower air conditioned building (group A), a prevalence of 25% in 36 persons working in a dry-heat air conditioned building (group B), a prevalence of 16% in 87 underground construction workers (group C) and a prevalence of 1.2% in 150 healthy blood donors with none of the above risk factors (group D). There is statistical significance between D and B and C.