Patient-controlled tissue collection for genetic testing after early pregnancy loss: A pilot study

Economic impact of using maternal plasma cell-free DNA testing to guide further workup in recurrent pregnancy loss

Objective

We have previously demonstrated that maternal‐plasma cell‐free DNA (cfDNA)‐testing can detect chromosomal anomalies in recurrent pregnancy loss (RPL) with 81.8% sensitivity and 90.3% specificity. Here we assess whether this is cost effective in guiding further workup in RPLs.

Method

A decision‐analytic model was developed to compare the cost of various RPL management pathways: (1) current American Society for Reproductive Medicine (ASRM) RPL workup; (2) microarray or karyotyping analysis of products of conception (POCs) and RPL workup only for euploid cases; and (3) cfDNA testing and RPL workup only for euploid cases. Sample accessibility, failure rates, and sensitivity were specified for each test. Costs of sample collection, genetic tests, and RPL workup were considered. Analysis outcomes included detection rate of chromosomal anomaly and cost per patient tested.

Results

In comparison to existing cytogenetic testing on POCs, cfDNA testing pathway allowed for better sample accessibility with a lower cost per patient. In addition, using cfDNA to guide further workup significantly increases the number of causative fetal chromosome anomalies detected, reducing the number of patients undergoing unnecessary workup resulting in an overall cost savings.

Conclusion

Our study showed that inclusion of cfDNA testing is a cost‐effective approach to guide RPL workup.

What is already known about this topic?

Chromosomal anomalies account for 50%–70% of early pregnancy loss (EPL) and even in recurrent pregnancy loss (RPL) random aneuploidy is the single most common etiology, accounting for >50% of cases.

In a previous study we have shown that maternal‐plasma genome‐wide cell‐free DNA (cfDNA)‐based testing can reliably detect chromosomal anomalies in random EPL and RPL with a sensitivity of 81.8% and a specificity of 90.3%.

We therefore suggested cfDNA‐based testing serve to guide further management in cases of RPL: if cfDNA in the second and subsequent RPL demonstrates aneuploidy, no further action is taken; if an unbalanced rearrangement is found, parental karyotyping is recommended; if no abnormality is detected, the recommended RPL workup is performed.

What does this study add?

In this study we demonstrate that using cfDNA to guide further workup in RPL is a cost‐effective approach.

We share our algorithm to facilitate local cost‐effectiveness analysis based on prevailing billing schemes, either based on national health systems or private payor systems.

Maternal plasma genome-wide cell-free DNA can detect fetal aneuploidy in early and recurrent pregnancy loss and can be used to direct further workup

STUDY QUESTION

Can maternal plasma cell-free DNA (cfDNA) detect chromosomal anomalies in early pregnancy loss (EPL) and recurrent pregnancy loss (RPL)?

SUMMARY ANSWER

Genome-wide cfDNA testing can serve as an alternative to cytogenetic analysis in products of conception (POCs) in RPLs and can guide further management.

WHAT IS KNOWN ALREADY

Random chromosomal anomalies are the single most common cause for EPL and RPL. Cytogenetic analysis in POCs may be used to direct management in RPL because the detection of random chromosomal anomalies can eliminate further unwarranted testing.

STUDY DESIGN, SIZE, DURATION

This was a prospective diagnostic test study from March 2018 to January 2019 of 109 patients experiencing pregnancy loss before 14 weeks gestation at a tertiary-care academic medical center.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Blood samples were drawn for genome-wide cfDNA testing prior to chorionic villous sampling for cytogenetic analysis of POCs with both short-term cultures (STCs) and long-term cultures (LTCs). Final analysis included 86 patients with non-mosaic cytogenetic results in POCs and available cfDNA results. Aneuploidy detection rates by cfDNA testing and POC cytogenetic analysis were compared. The first 50 samples served as the Training Set to establish pregnancy loss-specific log-likelihood ratio (LLR) thresholds using receiver-operator characteristic (ROC)-like analyses. These were then used for the entire cohort.

MAIN RESULTS AND THE ROLE OF CHANCE

Seventy-eight samples (71.5%) had results available from both STC and LTC; 12 samples (11%) had a result from STC only, and 7 samples (6.4%) had a result from LTC only. A chromosomal anomaly was detected in 55/86 (64%). The rates of chromosomal anomalies were 61, 72, 73 and 44% in patients undergoing their first, second, third and ≥4th pregnancy losses, respectively. The median cfDNA fetal fraction was 5%. With standard LLR thresholds used for noninvasive prenatal screening, the sensitivity of cfDNA in detecting aneuploidy was 55% (30/55) and with a specificity of 100% (31/31). Using pregnancy loss-specific LLR thresholds, the sensitivity of cfDNA in detecting aneuploidy was 82% (45/55), with a specificity of 90% (28/31). The positive and negative likelihood ratios were 8.46 and 0.20, respectively. Fetal sex was correctly assigned in all cases.

LIMITATIONS, REASONS FOR CAUTION

Cases with a false-positive result by cfDNA analysis would not receive the indicated RPL workup. Specificity could be improved by using a fetal fraction (FF) cutoff of 4%, but this would result in exclusion of more than a quarter of cases.

WIDER IMPLICATIONS OF THE FINDINGS

cfDNA-based testing can serve as an alternative to POC cytogenetic analysis and can guide further RPL management: if cfDNA demonstrates aneuploidy, no further action is taken and if no abnormality is detected, the recommended RPL workup is performed.

STUDY FUNDING/COMPETING INTEREST(S)

Cell-free DNA testing was funded by Illumina, Inc., San Diego, CA. Y.Y. is a member of Illumina’s Clinical Expert Panel and has received travel grants. A.B. has received travel grants from Illumina. All authors have no competing interest to declare.