Prenatal cell-free DNA screening for chromosomal aneuploidies after euploid embryo transfer shows high concordance with preimplantation genetic testing for aneuploidy results and low positive predictive values
Bibliographic record
Abstract
OBJECTIVE: To evaluate the positive predictive value (PPV) of prenatal cell-free DNA (cfDNA) screening for chromosomal aneuploidies in pregnancies achieved either after single euploid transfer in in vitro fertilization or Preimplantation Genetic Testing for Aneuploidy (PGT-A) cycles or transfer of single untested embryo, and to assess the concordance of prenatal-cfDNA-screening and PGT-A results. DESIGN: Single center retrospective cohort study. SETTING: Fertility clinic. PATIENT(S): A total of 2,973 prenatal-cfDNA-screening results for the most common trisomies (T13, T18, T21, X, and Y) and microdeletions (1p36, 4p16.3, 5p15.2, 15q11.2, and 22q11.2) from singleton pregnancies allocated into two groups: PGT-A group (n = 1,204) pregnant after single euploid transfer and non-PGT-A group (n = 1769) pregnant after transfer of single untested embryo, between 2016 and 2023. INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE(S): The primary outcome measure was the accuracy of prenatal-cfDNA screening. Positive and negative prenatal-cfDNA-screening results and subsequent prenatal or postnatal diagnostic testing were used to classify each positive prenatal-cfDNA-screening result as a true or a false positive. Secondary endpoints were to evaluate the concordance of PGT-A and prenatal-cfDNA-screening results and to assess the differences in the fetal fraction of cfDNA used for prenatal-cfDNA-screening reports between the study groups. RESULT(S): Prenatal-cfDNA screening was performed at a mean 11.3 ± 1.8 weeks gestational age, and yielded results in 99.9% of the patients (0.1% cancellation rate). There was no difference in the fetal fraction between PGT-A tested and not tested pregnancies (9.5% ± 4% vs. 10.3% ± 4%). 13 positive prenatal-cfDNA-screening results (two T21, two X0, four XXX, one XYY, one indeterminate sex, two 22q11 del/dup, and one 15q11.2del) were received for PGT-A group. Only one (22q11 dup) was confirmed with amniocentesis and fetal autopsy, giving a PPV for an abnormal prenatal-cfDNA screening of 7.7%, the rest had results concordant with PGT-A. Sex chromosomes were 100% concordant between prenatal-cfDNA-screening and PGT-A results, giving a 100% PPV for PGT-A for sex chromosomes and 100% negative predictive value for aneuploidies. Positive prenatal-cfDNA-screening results were received for 27 pregnancies from untested embryos (1.5%), follow-up testing was electively performed for 21, and 8 had confirmed the prenatal-cfDNA-screening result, giving a PPV for the non-PGT-A group of 38%. CONCLUSION(S): This study demonstrates that patients undergoing in vitro fertilization/PGT-A and single euploid embryo transfer can reliably do prenatal-cfDNA screening during their first trimester. Fetal fraction in singleton pregnancies after PGT-A tested embryos is not different from pregnancies with untested embryos. Positive predictive value for an abnormal prenatal-cfDNA-screening result after euploid embryo transfer was reassuringly low (7.7%). PGT-A reliably selects against aneuploidy with 100% concordance with fetal sex.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.015 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".