Cell-free DNA analysis for noninvasive examination of trisomy.

BACKGROUND: Cell-free DNA (cfDNA) testing for fetal trisomy is highly effective among high-risk women. However, there have been few direct, well-powered studies comparing cfDNA testing with standard screening during the first trimester in routine prenatal populations. METHODS: In this prospective, multicenter, blinded study conducted at 35 international centers, we assigned pregnant women presenting for aneuploidy screening at 10 to 14 weeks of gestation to undergo both standard screening (with measurement of nuchal translucency and biochemical analytes) and cfDNA testing. Participants received the results of standard screening; the results of cfDNA testing were blinded. Determination of the birth outcome was based on diagnostic genetic testing or newborn examination. The primary outcome was the area under the receiver-operating-characteristic curve (AUC) for trisomy 21 (Down's syndrome) with cfDNA testing versus standard screening. We also evaluated cfDNA testing and standard screening to assess the risk of trisomies 18 and 13. RESULTS: Of 18,955 women who were enrolled, results from 15,841 were available for analysis. The mean maternal age was 30.7 years, and the mean gestational age at testing was 12.5 weeks. The AUC for trisomy 21 was 0.999 for cfDNA testing and 0.958 for standard screening (P=0.001). Trisomy 21 was detected in 38 of 38 women (100%; 95% confidence interval [CI], 90.7 to 100) in the cfDNA-testing group, as compared with 30 of 38 women (78.9%; 95% CI, 62.7 to 90.4) in the standard-screening group (P=0.008). False positive rates were 0.06% (95% CI, 0.03 to 0.11) in the cfDNA group and 5.4% (95% CI, 5.1 to 5.8) in the standard-screening group (P<0.001). The positive predictive value for cfDNA testing was 80.9% (95% CI, 66.7 to 90.9), as compared with 3.4% (95% CI, 2.3 to 4.8) for standard screening (P<0.001). CONCLUSIONS: In this large, routine prenatal-screening population, cfDNA testing for trisomy 21 had higher sensitivity, a lower false positive rate, and higher positive predictive value than did standard screening with the measurement of nuchal translucency and biochemical analytes. (Funded by Ariosa Diagnostics and Perinatal Quality Foundation; NEXT ClinicalTrials.gov number, NCT01511458.).

Clinical performance of non-invasive prenatal testing (NIPT) using targeted cell-free DNA analysis in maternal plasma with microarrays or next generation sequencing (NGS) is consistent across multiple controlled clinical studies.

OBJECTIVE: To evaluate the clinical performance of non-invasive prenatal testing for trisomy 21, 18, and 13 using targeted cell-free DNA (cfDNA) analysis. METHODS: Targeted cfDNA analysis using DANSR™ and FORTE™ with microarray quantitation was used to evaluate the risk of trisomy 21, 18, and 13 in blinded samples from 799 singleton, twin, natural, and IVF pregnancies. Subjects either had fetal chromosome evaluation by karyotype, FISH, QF-PCR, or karyotype for newborns with suspected aneuploidy at birth. The results of targeted cfDNA analysis were compared to clinical genetic testing outcomes to assess clinical performance. RESULTS: Targeted cfDNA analysis with microarray quantification identified 107/108 trisomy 21 cases (99.1%), 29/30 trisomy 18 cases (96.7%), and 12/12 trisomy 13 cases (100%). The specificity was 100% for all three trisomies. Combining this data with all published clinical performance studies using DANSR/FORTE methodology for greater than 23 000 pregnancies, the sensitivity of targeted cfDNA analysis was calculated to be greater than 99% for trisomy 21, 97% for trisomy 18, and 94% for trisomy 13. Specificity for each trisomy was greater than 99.9%. CONCLUSION: Targeted cfDNA analysis demonstrates consistently high sensitivity and extremely low false positive rates for common autosomal trisomies in pregnancy across quantitation platforms.

Regional multidisciplinary team approach to the management of placenta accreta spectrum disorder.

OBJECTIVE: Patients with suspected placenta accreta spectrum (PAS) disorder are often referred to specialized medical centers for antepartum management and definitive treatment via cesarean hysterectomy. In 2019, our institution formed the only multidisciplinary team for the management of PAS within two of the largest counties in California. The purpose of this study was to evaluate the effects of the multidisciplinary team on patient volume and surgical outcomes for patients with PAS. METHODS: This was a single center retrospective cohort study, based in the only tertiary referral center within two of the largest counties in California. Patients who underwent cesarean hysterectomy for suspected PAS from January 2014 to April 2021 were included and divided into two groups, based on management by the multidisciplinary team from January 2019 and onward or routine care prior to that time. The outcomes of interest were quantitative blood loss, total units of packed red blood cell transfusion, referral volume, and diagnostic accuracy as well as ICU admission, bladder injury, and postoperative length of stay. Furthermore, we wanted to determine if patient's distance to the hospital impacted outcomes. Normally distributed variables were compared between groups using the t-test. Categorical variables were compared between the two groups using the chi square test. RESULTS: A total of 114 patients were included in the cohort, 59 patients were from January 2014 to December 2018 and 55 patients were from January 2019 to April 2021. Since the establishment of the multidisciplinary center, there was a 2.5-fold increase in the total patient volume (0.8 case/month to 2 cases/month) and a 2.8-fold increase in the referred patient volume. Patients undergoing cesarean hysterectomy since the establishment of the multidisciplinary team had less quantitative blood loss (1500 mL vs 2000 mL, p = .005) and required less units of packed red blood cell transfusion (2 vs 4 units, p < .001). In addition, blood loss of ≥2000 mL decreased from 57.6% to 38.2% (p = .04) and diagnostic accuracy improved from 35.6% to 83.6% (p < .001). Furthermore, we found that patient distance to the hospital did not significantly impact surgical outcomes. CONCLUSIONS: Since the establishment of the multidisciplinary team, our center experienced an increase in PAS volume and was able to demonstrate a statistically significant improvement in patient outcomes.

Non-Invasive Chromosomal Evaluation (NICE) Study: results of a multicenter prospective cohort study for detection of fetal trisomy 21 and trisomy 18.

OBJECTIVE: We sought to evaluate performance of a noninvasive prenatal test for fetal trisomy 21 (T21) and trisomy 18 (T18). STUDY DESIGN: A multicenter cohort study was performed whereby cell-free DNA from maternal plasma was analyzed. Chromosome-selective sequencing on chromosomes 21 and 18 was performed with reporting of an aneuploidy risk (High Risk or Low Risk) for each subject. RESULTS: Of the 81 T21 cases, all were classified as High Risk for T21 and there was 1 false-positive result among the 2888 normal cases, for a sensitivity of 100% (95% confidence interval [CI], 95.5-100%) and a false-positive rate of 0.03% (95% CI, 0.002-0.20%). Of the 38 T18 cases, 37 were classified as High Risk and there were 2 false-positive results among the 2888 normal cases, for a sensitivity of 97.4% (95% CI, 86.5-99.9%) and a false-positive rate of 0.07% (95% CI, 0.02-0.25%). CONCLUSION: Chromosome-selective sequencing of cell-free DNA and application of an individualized risk algorithm is effective in the detection of fetal T21 and T18.

The fetal fraction of cell-free DNA in maternal plasma is not affected by a priori risk of fetal trisomy.

OBJECTIVE: To determine the relationship between a priori risk for fetal trisomy and the fraction of fetal cell-free DNA (cfDNA) in maternal blood. METHODS: A comparative analysis on fetal cfDNA amounts was performed in subjects stratified into a priori risk groups based on maternal age, prenatal screening results, or nuchal translucency measurement. RESULTS: Across the highest and lowest deciles within each group, there were no significant differences in the fetal cfDNA fraction. CONCLUSIONS: These data support the concept that non-invasive prenatal test performance as determined by fetal cfDNA fraction is not predicted to be different based on patient risk classification.