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.

The indications for early prenatal diagnosis of trisomy 18: a 7-year experience at mainland China.

Objective: To report the experience with first-trimester prenatal detection of pregnancies complicated by trisomy 18.Study design: Proven cases of trisomy 18 identified between 11 and 14 weeks of gestation were retrospectively reviewed. Information on maternal demographics, prenatal sonographic findings, indications for prenatal diagnosis and chromosomal analysis results was obtained by reviewing medical records.Results: During the 7-year period from January 2011 to December 2017, 89 cases of full trisomy 18 had first-trimester indications for prenatal diagnosis at Guangzhou Women and Children's Medical Center. Eighty-five (95.5%) had abnormal sonographic findings in the first trimester. The most common finding was increased nuchal translucency (55.1%), followed by cystic hygroma (18.0%), omphalocele (14.6%), and fetalis hydrops (11.2%). Four cases (4.5%) were not associated with any abnormal first-trimester sonographic finding, and were diagnosed because of routine positive screening results for trisomy 18. A single case was diagnosed because of a positive cell-free DNA (cfDNA) result.Conclusion: These results demonstrate that a large number of fetuses with trisomy 18 have abnormal sonographic findings in the first trimester, and support the continued utility of first-trimester sonographic examination in the diagnosis of this trisomy even with the availability of cfDNA.

Diagnosis of major heart defects by routine first-trimester ultrasound examination: association with increased nuchal translucency, tricuspid regurgitation and abnormal flow in ductus venosus.

OBJECTIVE: To examine the association between fetal major heart defects and increased nuchal translucency thickness (NT), tricuspid regurgitation and abnormal flow in the ductus venosus in a large population of singleton pregnancies undergoing routine ultrasound examination at 11-13 weeks' gestation. METHODS: This was a retrospective study of prospectively collected data from singleton pregnancies attending for a routine ultrasound scan at 11-13 weeks' gestation, which included examination of fetal anatomy, measurement of NT and assessment of blood flow across the tricuspid valve and in the ductus venosus, according to a standardized protocol. The incidence of fetal NT ≥ 95th and ≥ 99th percentiles, tricuspid regurgitation and reversed a-wave in the ductus venosus in fetuses with and those without a major heart defect was determined and the performance of each marker and their combination in the detection of major heart defects was calculated. RESULTS: The study population of 93 209 pregnancies with no apparent chromosomal abnormality included 211 (0.23%) with a fetal major heart defect and 92 998 morphologically normal neonates. In 113 (53.6%) cases with a major heart defect, the diagnosis was made at the 11-13-week scan, in 82 (38.9%) at the 18-24-week scan, in 10 (4.7%) at the third-trimester scan and in six (2.8%) postnatally. At the 11-13-week scan, we diagnosed all cases of tricuspid or pulmonary atresia and polyvalvular dysplasia, > 90% of cases of hypoplastic left heart syndrome or atrioventricular septal defect, about 60% of complex heart defects and cases of left atrial isomerism (interrupted inferior vena cava with normal intracardiac anatomy), 30-40% of cases of tetralogy of Fallot and arch abnormalities, 25% of tricuspid valve abnormalities and about 15% of cases of transposition of the great arteries, but none of aortic or pulmonary stenosis or common arterial trunk. Fetal NT ≥ 95th or ≥ 99th percentile, tricuspid regurgitation or abnormal ductus venosus flow was observed in 77 (36.5%), 45 (21.3%), 61 (28.9%) and 58 (27.5%) fetuses with a major heart defect, respectively, and in 5678 (6.1%), 857 (0.9%), 1136 (1.2%) and 1644 (1.8%) of those without a heart defect. Any one of NT ≥ 95th percentile, tricuspid regurgitation or abnormal flow in the ductus venosus was found in 117 (55.5%; 95% CI, 48.5-62.3%) fetuses with a heart defect and in 8166 (8.8%; 95% CI, 8.6-9.0%) of those without a heart defect. Any one of NT ≥ 99th percentile or the other two markers was found in 99 (46.9%; 95% CI, 40.0-53.9%) fetuses with a heart defect and in 3517 (3.8%; 95% CI, 3.7-3.9%) of those without a heart defect. CONCLUSION: At 11-13 weeks' gestation, measurement of fetal NT and assessment of flow across the tricuspid valve and in the ductus venosus can lead to early diagnosis of major heart defect. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Increased nuchal translucency at 11-13 weeks' gestation and outcome in twin pregnancy.

OBJECTIVE: To investigate the value of increased fetal nuchal translucency thickness (NT) at the 11-13-week scan in the prediction of adverse outcome in dichorionic (DC), monochorionic diamniotic (MCDA) and monochorionic monoamniotic (MCMA) twin pregnancies. METHODS: This was a retrospective analysis of prospectively collected data on twin pregnancies undergoing routine ultrasound examination at 11-13 weeks' gestation between 2002 and 2019. In pregnancies with no major defects or chromosomal abnormalities, we examined the value of increased NT ≥ 95th percentile in one or both fetuses in the prediction of, first, miscarriage or death of one or both fetuses at < 20 and < 24 weeks' gestation in DC, MCDA and MCMA twin pregnancies, second, death of one or both fetuses or neonates at ≥ 24 weeks in DC, MCDA and MCMA twin pregnancies, third, development of twin-twin transfusion syndrome (TTTS) or selective fetal growth restriction (sFGR) treated by endoscopic laser surgery at < 20 and ≥ 20 weeks' gestation in MCDA pregnancies, and, fourth, either fetal loss or laser surgery at < 20 weeks' gestation in MCDA pregnancies. RESULTS: The study population of 6225 twin pregnancies included 4896 (78.7%) DC, 1274 (20.5%) MCDA and 55 (0.9%) MCMA pregnancies. The incidence of NT ≥ 95th percentile in one or both fetuses in DC twin pregnancies was 8.3%; in MCDA twins the incidence was significantly higher (10.4%; P = 0.016), but in MCMA twins it was not significantly different (9.1%; P = 0.804) from that in DC twins. In DC twin pregnancies, the incidence of high NT was not significantly different between those with two survivors and those with adverse outcome. In MCMA twin pregnancies, the number of cases was too small for meaningful assessment of the relationship between high NT and adverse outcome. In MCDA twin pregnancies with at least one fetal death or need for endoscopic laser surgery at < 20 weeks' gestation, the incidence of NT ≥ 95th percentile was significantly higher than in those with two survivors (23.5% vs 9.8%; P < 0.0001). Kaplan-Meier analysis in MCDA twin pregnancies showed that, in those with NT ≥ 95th percentile, there was significantly lower survival at < 20 weeks' gestation than in those with NT < 95th percentile (P = 0.001); this was not the case for survival at ≥ 20 weeks (P = 0.960). The performance of screening by fetal NT ≥ 95th percentile for prediction of either fetal loss or need for endoscopic laser surgery at < 20 weeks' gestation was poor, with a detection rate of 23.5% at a false-positive rate of 8.9%, and the relative risk, in comparison to fetal NT < 95th percentile, was 2.640 (95% CI, 1.854-3.758; P < 0.0001). In MCDA twin pregnancies, the overall rate of fetal loss or need for laser surgery at < 20 weeks' gestation was 10.7% but, in the subgroups with NT ≥ 95th and NT ≥ 99th percentiles, which constituted 10.4% and 3.3% of the total, the rates increased to 24.1% and 40.5%, respectively. CONCLUSIONS: In MCDA twin pregnancies with no major fetal abnormalities, measurement of NT at the 11-13-week scan is a poor screening test for adverse pregnancy outcome. However, the finding in one or both fetuses of NT ≥ 95th percentile, and more so ≥ 99th percentile, is associated with a substantially increased risk of fetal loss or need for endoscopic laser surgery at < 20 weeks' gestation. The extent to which closer monitoring and earlier intervention in the high-risk group can reduce these complications remains to be determined. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

The clinical usefulness of biochemical (free ß-hCg, PaPP-a) and ultrasound (nuchal translucency) parameters in prenatal screening of trisomy 21 in the first trimester of pregnancy.

OBJECTIVES: The aim of the study was to analyze the correlation of multiples of the normal median of PAPP-A, free ß-hCG levels and nuchal translucency values in prenatal, first trimester screening of trisomy 21 in pregnant women. MATERIAL AND METHODS: 251 pregnant women underwent antenatal screening at 11-13+6 weeks of pregnancy which was composed of the measurement of free ß-human chorionic gonadotropin (ß-hCG) and pregnancy-associated plasma protein (PAPP-A) levels in the maternal serum and an ultrasound assessment of nuchal translucency (NT). The pregnant women with a high risk of trisomy 21 (≥ 1:300) were given amniocentesis to verify fetal defects. There were 217 cases of normal fetal karyotype and 34 cases of trisomy 21. PAPP-A, ß-hCGMoM and NT values were analyzed for the predefined ranges. RESULTS: 85% cases of trisomy 21 had elevated free ß-hCGMoM (> 1.5) and only 53% of these had a PAPP-AMoM result below 0.5 (p < 0.05). Analysis of NT in selected ranges of ß-hCG (> 1.5) and PAPP-AMoM (< 0.05), which are typical for Down Syndrome values, showed that not all fetuses with Down Syndrome presented with an increased NT. Respectively 44.15% and 26.5% of fetuses presented with increased NT. Characteristic for trisomy 21, a correlation with all 1st trimester screening tests' parameters occurred in only 23.5% of cases. In 53% of cases the results were atypical. CONCLUSIONS: The PAPP-A and ß-hCG values in the selected MoM ranges did not shown a correlation to the NT measurement, therefore they are independent factors in the diagnosis of trisomy 21. Simultaneous biochemical and ultrasound testing is an indispensable condition for prenatal diagnosis of trisomy 21 in the 1st trimester of pregnancy.

First trimester cystic hygroma colli: Retrospective analysis in a tertiary center.

OBJECTIVE: This retrospective study aims to evaluate the incidence, presence of chromosomal anomalies and outcome of fetuses diagnosed with cystic hygroma colli in the first trimester in a single tertiary center. STUDY DESIGN: A retrospective study was performed over a ten-years period from 2007 to 2017 of all fetuses with a first-trimester diagnosis of cystic hygroma. Maternal and fetal parameters were assessed with descriptive statistics. RESULTS: A total of 185 singleton pregnancies were included. Chromosomal anomalies were present in 122 cases (65.9%). Sixty-three fetuses (34.1%) had a normal karyotype. Noonan syndrome was diagnosed in 6 cases using additional testing for RASopathies. In euploid fetuses, a major congenital anomaly was detected in 35 of 63 cases (56%) and if present, 91.4% had an abnormal fetal outcome compared to 32.1% if no structural anomaly was found (p < 0.01). Fetuses with a nuchal translucency thickness more than 10 mm and hydropic fetuses had a worse outcome. DISCUSSION: Associated structural anomalies or hydrops fetalis are significant predictors for an abnormal outcome in pregnancies with first-trimester cystic hygroma and a normal karyotype. Cytogenetic evaluation and detailed sonographic evaluation are of great importance in the determination of the prognosis of pregnancies complicated by first-trimester cystic hygroma.

Effectiveness of 12-13-week scan for early diagnosis of fetal congenital anomalies in the cell-free DNA era.

OBJECTIVES: The main aim of this study was to assess the proportion and type of congenital anomalies, both structural and chromosomal, that can be detected at an early scan performed at 12-13 weeks' gestation, compared with at the 20-week structural anomaly scan offered under the present screening policy. Secondary aims were to evaluate the incidence of false-positive findings and ultrasound markers at both scans, and parental choice regarding termination of pregnancy (TOP). METHODS: Sonographers accredited for nuchal translucency (NT) measurement were asked to participate in the study after undergoing additional training to improve their skills in late first-trimester fetal anatomy examination. The early scans were performed according to a structured protocol, in six ultrasound practices and two referral centers in the north-east of The Netherlands. All women opting for the combined test (CT) or with an increased a-priori risk of fetal anomalies were offered a scan at 12-13 weeks' gestation (study group). All women with a continuing pregnancy were offered, as part of the 'usual care', a 20-week anomaly scan. RESULTS: The study group consisted of 5237 women opting for the CT and 297 women with an increased a-priori risk of anomalies (total, 5534). In total, 51 structural and 34 chromosomal anomalies were detected prenatally in the study population, and 18 additional structural anomalies were detected after birth. Overall, 54/85 (63.5%) anomalies were detected at the early scan (23/51 (45.1%) structural and all chromosomal anomalies presenting with either an increased risk at first-trimester screening or structural anomalies (31/34)). All particularly severe anomalies were detected at the early scan (all cases of neural tube defect, omphalocele, megacystis, and multiple severe congenital and severe skeletal anomalies). NT was increased in 12/23 (52.2%) cases of structural anomaly detected at the early scan. Of the 12 cases of heart defects, four (33.3%) were detected at the early scan, five (41.7%) at the 20-week scan and three (25.0%) after birth. False-positive diagnoses at the early scan and at the 20-week scan occurred in 0.1% and 0.6% of cases, respectively, whereas ultrasound markers were detected in 1.4% and 3.0% of cases, respectively. After first- or second-trimester diagnosis of an anomaly, parents elected TOP in 83.3% and 25.8% of cases, respectively. CONCLUSIONS: An early scan performed at 12-13 weeks' gestation by a competent sonographer can detect about half of the prenatally detectable structural anomalies and 100% of those expected to be detected at this stage. Particularly severe anomalies, often causing parents to choose TOP, are amenable to early diagnosis. The early scan is an essential part of modern pregnancy care. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Chromosomal microarray as primary diagnostic genomic tool for pregnancies at increased risk within a population-based combined first-trimester screening program.

OBJECTIVE: To evaluate the performance of high-resolution chromosomal microarray (CMA) as the standard diagnostic approach for genomic imbalances in pregnancies with increased risk based on combined first-trimester screening (cFTS). METHODS: This was a retrospective study of genomic findings in a cohort of 575 consecutive pregnancies undergoing invasive testing because of a cFTS risk ≥ 1:300 on a publicly funded population-based screening program in the Central and Northern Regions of Denmark, between September 2015 and September 2016. Women with fetal nuchal translucency thickness ≥ 3.5 mm or opting for non-invasive prenatal testing (NIPT) were excluded. Comparative genomic hybridization was performed using a 180-K oligonucleotide array on DNA extracted directly from chorionic villus/amniocentesis samples. Genomic outcomes were reported in relation to cFTS findings. RESULTS: Of the 575 pregnancies that underwent invasive testing, CMA detected 22 (3.8% (95% CI, 2.5-5.7%)) cases of trisomies 21, 18 and 13, 14 (2.4% (95% CI, 1.4-4.0%)) cases of other types of aneuploidy and 15 (2.6% (95% CI, 1.5-4.3%)) cases with a pathogenic or probably pathogenic copy number variant (CNV). Of the 15 CNVs, three were > 10 Mb and would probably have been detected by chromosomal analysis, but the other 12 would most probably not have been detected using conventional cytogenetic techniques; therefore, the overall detection rate of CMA (8.9% (95% CI, 6.8-11.5%)) was significantly higher than that estimated for conventional cytogenetic analysis (6.8% (95% CI, 5.0-9.1%)) (P = 0.0049). Reducing the cFTS risk threshold for invasive diagnostic testing to 1 in 100 or 1 in 50 would have led, respectively, to 60% or 100% of the pathogenic CNVs being missed. CONCLUSIONS: CMA is a valuable diagnostic technique that can identify an increased number of genomic aberrations in pregnancies at increased risk on cFTS. Limiting diagnostic testing to pregnancies with a risk above 1 in 100 or 1 in 50, as proposed in contingent NIPT/invasive testing models, would lead to a significant proportion of pathogenic CNVs being missed at first-trimester screening. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Inequity in timing of prenatal screening in New Zealand: Who are our most vulnerable?

BACKGROUND: In New Zealand (NZ), Maori and Pacific women are less likely to complete prenatal screening for Down syndrome and other aneuploidies than other ethnic groups. Young women <20 have low rates of completed screening compared with women >20 years. Women living in deprived areas have lower completed screen rates than women living in more affluent areas. Combined first trimester screening has a superior sensitivity (85%) compared with second trimester screening (75%) for trisomy 21. The relative contribution of demographic factors to timing of screening uptake (first vs second trimester) has not previously been examined. AIM: To evaluate the association of ethnicity, deprivation, District Health Board (DHB) of domicile and maternal age with timing of prenatal screening (first vs second trimester) in pregnant women screened in NZ from 2010 to 2013. METHODS AND MATERIALS: Univariate logistic regression analyses were used to explore the association between timing of completed screening and each of ethnicity, deprivation index, DHB of domicile and maternal age. Multivariate logistic regression models were developed to calculate odds ratios (OR) and 95% confidence intervals (CI). Statistical analyses were performed using SAS v9.3 RESULTS: Of completed prenatal screens, 88% were completed in the first trimester. Ethnicity, age, deprivation and DHB were all significant predictors of completed first versus second trimester screening. Maori women were almost 60% less likely (adjusted OR 0.37, CI 0.35-0.39) and Pacific women almost 80% less likely (adjusted OR 0.23, CI 0.21-0.24) than NZ European women to have completed first versus second trimester screening. Women <30 years were less likely to have completed first trimester screening, as were more deprived women. Variation was also seen by DHB with women living in Whanganui DHB less likely to have completed first versus second trimester screening than women living in Auckland (adjusted OR 0.76, CI 0.71-0.81). Women living in Bay of Plenty DHB were more likely to be screened in the first versus second trimester compared with women living in Auckland (adjusted OR 1.55, CI 1.38-1.74). Within Auckland itself, women living in Counties Manukau DHB were less likely to be screened in the first versus second trimester than women living in Auckland DHB even after adjusting for ethnicity, deprivation and maternal age. CONCLUSION: Maori and Pacific women have the lowest uptake of completed first versus second trimester screening after adjusting for age, deprivation and DHB. Research is required to understand if this relates to characteristics of the carer making the offer of screening, language and/or cultural barriers to care or specific collective cultural or religious views held by women from these ethnicities. The lower completed first trimester versus second trimester prenatal screening in deprived areas, as well as variation by DHB, may relate to the availability of ultrasound and/or laboratory services in specific regions. Cost may be a contributing factor to inequity in timing of completed prenatal screening uptake, as first trimester screening incurs a part-charge to the individual, while second trimester screening is fully funded. Systemic factors within the NZ maternity model of care may also be contributory with a potential disconnect occurring for the woman between primary medical care and later registration with a Lead Maternity Carer in the first trimester.

Does progesterone therapy increase nuchal translucency in women with threatened miscarriage?

OBJECTIVES: The effect of exogenous progesterone on fetal nuchal translucency (NT) has been proposed recently. In this study, we aimed to compare the thickness of NT of patients receiving and not receiving progesterone for threatened miscarriage. MATERIAL AND METHODS: This study was designed as a retrospective comparative study. Ninety five women treated with progesterone constituted the study group whereas 97 women who were not treated with progesterone constituted the control group. An ultrasonographic examination was performed on all of the women to measure NT. All patients were treated with oral micronized progesterone in the study group. The main parameters recorded for each woman were; age, body mass index (BMI), obstetrical characteristics, and gestational age at first examination, treatment duration of progesterone therapy, and results of combined and triple tests. RESULTS: A total of 192 pregnant women with threatened miscarriage were included in this study. The mean NT thickness was statistically significantly higher in the study group (p < 0.001), and mean serum level of human chorionic gonadotropin (hCG) was also higher in this group (p < 0.05). There was no statistically significant difference between groups in terms of age, BMI, and gestational age at first examination. ROC curve analysis demonstrated that only increased NT (area under the curve: 0.634, p = 0.005, 95% CI: 0.541-0.727) was a discriminative factor for women receiving progesterone for threatened miscarriage. Also there was a positive correlation between NT and treatment duration (r = 0.269; p < 0.001). CONCLUSIONS: We think that oral progesterone therapy may increase NT depending on treatment duration without causing abnormal prenatal screening test results.

Use of the Combined First-Trimester Screen in High- and Low-Risk Patient Populations After Introduction of Noninvasive Prenatal Testing.

OBJECTIVES: To report changes in the use of the combined first-trimester screen (FTS) in patients classified as high and low risk for fetal aneuploidy, including after introduction of noninvasive prenatal testing (NIPT). METHODS: A prospectively collected database was reviewed to investigate changes in FTS use before and after American College of Obstetricians and Gynecologists (ACOG) Practice Bulletin No. 77 (Obstet Gynecol 2007; 109:217-227), which recommended that all patients be offered aneuploidy screening, and after NIPT introduction. High-risk patients were classified as 35 years or older at the estimated time of delivery or those with an abnormal prior screen, abnormal ultrasound findings, or family history of aneuploidy. Data were normalized per 100 morphologic ultrasound examinations to account for changes in patient number over time. Statistical significance was defined as P < .05. RESULTS: A total of 10,125 FTSs were recorded during the 88-month study period, including 2962 in high-risk patients and 7163 in low-risk patients. The total number of FTSs performed per 100 morphologic ultrasound examinations significantly increased after ACOG Practice Bulletin No. 77 and significantly decreased after NIPT introduction. In high-risk patients, the total number of FTSs performed per 100 morphologic ultrasound examinations significantly increased after ACOG Practice Bulletin No. 77 but significantly decreased after NIPT introduction. In contrast, in low-risk patients, the total number of FTSs performed per 100 morphologic ultrasound examinations significantly increased after ACOG Practice Bulletin No.77 but was not statistically different after NIPT introduction. CONCLUSIONS: American College of Obstetricians and Gynecologists Practice Bulletin No. 77 significantly increased patient use of FTS. The introduction of NIPT significantly decreased FTS use in the high-risk population but not in the low-risk population.

Uptake of noninvasive prenatal testing at a large academic referral center.

OBJECTIVE: Noninvasive prenatal testing (NIPT) is a recently developed risk-assessment technique with high sensitivity and specificity for fetal aneuploidy. The effect NIPT has had on traditional screening and diagnostic testing has not been clearly demonstrated. In this study, NIPT uptake and subsequent changes in the utilization of first-trimester screen (FTS), chorionic villus sampling (CVS), and amniocentesis in a single referral center is reported. STUDY DESIGN: Monthly numbers of NIPT (in high-risk patients), FTS, CVS, and amniocentesis were compared between a 35-month baseline period (April 2009 through February 2012) before introduction of NIPT, and the initial 16 months following NIPT introduction divided in 4-month quarters beginning in March 2012 through June 2013. RESULTS: A total of 1265 NIPT, 6637 FTS, 251 CVS, and 1134 amniocentesis were recorded over the 51-month study period in singleton pregnancies of women who desired prenatal screening and diagnostic testing. NIPT became the predominant FTS method by the second quarter following its introduction, increasing by 55.0% over the course of the study period. Total first-trimester risk assessments (NIPT+FTS) were not statistically different following NIPT (P = .312), but average monthly FTS procedures significantly decreased following NIPT introduction, decreasing by 48.7% over the course of the study period. Average monthly CVS and amniocentesis procedures significantly decreased following NIPT introduction, representing a 77.2% and 52.5% decrease in testing, respectively. Screening and testing per 100 morphological ultrasounds followed a similar trend. CONCLUSION: NIPT was quickly adopted by our high-risk patient population, and significantly decreased alternate prenatal screening and diagnostic testing in a short period of time.

The price of performance: a cost and performance analysis of the implementation of cell-free fetal DNA testing for Down syndrome in Ontario, Canada.

OBJECTIVE: To examine the cost and performance implications of introducing cell-free fetal DNA (cffDNA) testing within modeled scenarios in a publicly funded Canadian provincial Down syndrome (DS) prenatal screening program. METHOD: Two clinical algorithms were created: the first to represent the current screening program and the second to represent one that incorporates cffDNA testing. From these algorithms, eight distinct scenarios were modeled to examine: (1) the current program (no cffDNA), (2) the current program with first trimester screening (FTS) as the nuchal translucency-based primary screen (no cffDNA), (3) a program substituting current screening with primary cffDNA, (4) contingent cffDNA with current FTS performance, (5) contingent cffDNA at a fixed price to result in overall cost neutrality,(6) contingent cffDNA with an improved detection rate (DR) of FTS, (7) contingent cffDNA with higher uptake of FTS, and (8) contingent cffDNA with optimized FTS (higher uptake and improved DR). RESULTS: This modeling study demonstrates that introducing contingent cffDNA testing improves performance by increasing the number of cases of DS detected prenatally, and reducing the number of amniocenteses performed and concomitant iatrogenic pregnancy loss of pregnancies not affected by DS. Costs are modestly increased, although the cost per case of DS detected is decreased with contingent cffDNA testing. CONCLUSION: Contingent models of cffDNA testing can improve overall screening performance while maintaining the provision of an 11- to 13-week scan. Costs are modestly increased, but cost per prenatally detected case of DS is decreased.

Utilization of available prenatal screening and diagnosis: effects of the California screen program.

OBJECTIVE: In 2009, the California Genetic Disease Branch introduced an aneuploidy screening program allowing Medi-Cal (state insured) patients access to state-sponsored first-trimester screening. The objective of this study was to assess the effect of greater access to prenatal screening on available resources at a single center. STUDY DESIGN: Data of prenatal screening and diagnostic procedures performed 4 months before the introduction of the program were compared with those of 12 months following the introduction. RESULT: Between December 2008 and March 2010, 7689 women underwent first trimester screening, 1286 underwent amniocentesis and 398 underwent chorionic villus sampling. When a comparison was made between the 4 months before and the 12 months after the program's introduction, a greater number of nuchal translucency (NT) examinations was seen to have been performed (384 per month vs 513 per month, P=0.001). Prenatal diagnostic procedures did not increase, but a greater proportion was performed for positive screen results. CONCLUSION: Introduction of the California screening program was associated with increased NT procedures and fewer invasive procedures for advanced maternal age.

False-negative results in routine combined first-trimester screening for down syndrome in Finland.

We analyzed the frequency and possible causes of false-negative (Fn) screening results in first-trimester combined Down syndrome screening in Finland. During the study period (May 1, 2002, to December 31, 2008), 76,949 voluntary women with singleton pregnancies participated in screening. Maternal age at screening, week of gestation, levels of pregnancy-associated plasma protein-A (PAPP-A), free ß-human chorionic gonadotropin (fß-hCG), and nuchal translucency (NT) measurement were compared and statistically analyzed between true-positive (Tp) and Fn cases. There were a total of 188 Down syndrome cases (1:409) in the screened population; 154 confirmed Tp and 34 Fn cases. Most Fn cases (n = 25) occurred at 12 + 0 to 13 + 6 weeks' gestation and only nine Fn cases presented between 10 and 11 weeks' gestation. According to the logistic regression analysis, the NT measurement was the most powerful discriminating factor in Fn screening results and accounted for 37.2% of Fn results. The second most important factor was fß-hCG, adding 14.0% to R(2), followed by PAPP-A, which contributed a further 14.3%. The chosen parameters explain 83.9% of Fn results, but 16.1% remain due to unknown factor(s). All investigated parameters contributed to Fn screening results, but fetal NT was the most discriminating factor leading to an Fn screening result.

Auditing ultrasound assessment of fetal nuchal translucency thickness: a review of Australian National Data 2002-2008.

BACKGROUND: Nuchal translucency (NT) measurement is the ultrasound component of first trimester combined screening for Down syndrome. In 2002, a NT ultrasound education and monitoring program was established in Australia. Between 2002 and 2008, a total of 728,502 NT scans were audited through this process. OVERALL AIM: To audit the availability and performance of certified operators measuring NT following implementation of the Australian education and monitoring program in 2002. METHODS: Retrospective review of the central database that is used to monitor performance of individuals and practices performing NT scans in both public and private practice settings throughout Australia between 2002 and 2008. The performance of operators was assessed by a widely used international standard - that 40-60% of NT measurements should be above the median value for gestational age. RESULTS: The number of certified operators has increased (from 184 in 2002 to 477 in 2008). There is wide variation between states in the number of operators per birth. The percentage of certified operators with a measurement distribution meeting the international standard has increased from 40% in 2002 to 55% in 2008. Greatest improvement has been seen in operators performing 30-199 scans per year. There has been no overall improvement in performance over the last three audit cycles. CONCLUSIONS: The number of operators certified to perform the NT scan has increased since 2002, although availability in some states remains low. An initial improvement in performance of operators appears to have reached a plateau. It is time to become more proactive in engaging operators in the audit cycle.

Undermeasurement of nuchal translucencies: implications for screening.

OBJECTIVE: To analyze the maximum nuchal translucency from 327 centers to determine whether a more-than-expected number of centers had maximum nuchal translucency of 2.5 mm or less (approximately 4% of nuchal translucency values should be 2.5 mm or higher). METHODS: We analyzed data from 182,669 nuchal translucency cases at centers in which at least 100 nuchal translucency examinations were performed from July 2008 through June 2009 and investigated the appropriateness of the distribution of values. We then investigated the likelihood of the skewing of the distribution seen using a 100 simulations of such modeled data. RESULTS: Based on a binomial distribution, the chance that a center would have no nuchal translucency values above 2.5 mm is 1.7% for 100 patients per center, and 0.2% for 150 patients per center. Additionally, the median multiples of the median should shift by approximately 2.5% if all nuchal translucency values higher than 2.5 mm are excluded from the population. Our data show that 7.3% of centers had a maximum nuchal translucency of to 2.5 mm or less, and more than 20% have never reported an nuchal translucency of greater than 3 mm. The maximum nuchal translucency at a center correlated positively with its median multiple of the median. Centers with no nuchal translucency values greater than 2.5 mm also have nearly 50% of their ultrasonographers with excessive low nuchal translucency (greater than 10% of cases less than fifth percentile). CONCLUSION: Too many centers have a maximum nuchal translucency of 2.5 mm or lower, low median nuchal translucency, and excessive low nuchal translucency, indicating that data from these centers are not representative of the expected distribution of nuchal translucencies. Our data suggest a systematic undermeasurement of nuchal translucency. LEVEL OF EVIDENCE: III.

Impact of quality of nuchal translucency measurements on detection rates of trisomies 13 and 18.

OBJECTIVE: To determine the relative contribution of nuchal translucency (NT) to the biochemical detection rates of combined screening for trisomies 13 and 18 in two healthcare systems practicing different quality-control systems of nuchal measurement. METHODS: De-identified data collected from the Fetal Medicine Foundation in the United Kingdom and laboratory data from NTD laboratories in the United States were compared for detection rate and false-positive rate (FPR) for combined trisomies 13 and 18 screening and were subcategorized by biochemical only and biochemistry combined with NT measurement. RESULTS: US and UK biochemical detection rates were virtually identical: 83% for a FPR of 1.8%. When NT measurement was added, the US rate increased to 88% for a 0.7 FPR, but in the UK the rate increased to 94% for a FPR of 0.3%. The mean NT was 1.69 mm in the US and 2.82 mm in the UK. CONCLUSIONS: NT measurement as practiced in the UK system with tight quality control significantly increased the detection rate and significantly reduced the FPR of combined screening for trisomies 13 and 18, when compared to the US with apparently less rigid quality control.

Use of the genetic sonogram in the United States in 2001 and 2007.

OBJECTIVE: The purpose of this study was to determine whether there have been changes in the use of second-trimester genetic sonograms and in the second-trimester sonographic markers used to screen for fetal aneuploidy by maternal-fetal medicine specialists in the United States from 2001 to 2007. METHODS: A survey was mailed to Society for Maternal-Fetal Medicine members in the United States in April 2007 inquiring about their practice patterns regarding the genetic sonogram. Specific sonographic markers used for risk adjustment as part of the genetic sonogram were also assessed. The responses from 2007 were compared with responses from a similar survey administered in 2001 (Am J Obstet Gynecol 2002; 187:1230-1234) using descriptive statistics, the chi(2) test, and the Wilcoxon rank sum test. RESULTS: A total of 991 responses were analyzed: 543 of 1638 (32%) in 2001 and 448 of 1756 (26%) in 2007. Significant increases (P < .0001) were noted in the number of specialists who used the genetic sonogram as a screening tool for Down syndrome and for every single sonographic marker used to adjust a woman's risk for having a fetus with Down syndrome during a genetic sonogram, except for choroid plexus cyst, clinodactyly, sandal gap toes, and widened pelvic angle. CONCLUSIONS: Practitioners in the United States are using an increasing number of second-trimester sonographic markers to help identify aneuploid fetuses. The growing acceptance of sonography to screen for fetal aneuploidy and the recommendation by the American College of Obstetricians and Gynecologists for universal screening suggest that more resources may be necessary to meet the growing demand for second-trimester sonograms.