Course / What is PGT-A?
Objective: To ground participants in the genetic and clinical concepts underlying PGT-A, and to understand the rationale for its use.
Content / Key Points:
Terminology and evolution: PGS → PGT-A (why the change)
Chromosomal abnormalities (aneuploidy, trisomy, monosomy, structural abnormalities)
Sources of embryonic aneuploidy (meiotic nondisjunction, mitotic errors, mosaicism)
Prevalence of chromosomal errors by maternal age and by embryo stage
Impact of aneuploidy on implantation, miscarriage, and live birth rates
Statistical basis: what proportion of embryos typically are euploid vs aneuploid in various age cohorts
Role of PGT-A as a selection tool (not a guarantee)
Learning Deliverables:
Chart: frequency of euploid embryos by maternal age
Illustration: origin of nondisjunction in meiosis I / II
Short quiz: define mosaicism, segmental aneuploidy
Objective: To explore how PGT-A helps reduce the risk of transferring chromosomally abnormal embryos, and to examine limitations and risk mitigation.
Content / Key Points:
Concept: reducing risk, not eliminating it
False positives / false negatives: sampling bias, mosaicism, dropout
Maternal contamination or DNA contamination risks
Embryo mosaicism: detection thresholds, classification, and clinical decision frameworks
Segmental aneuploidies and partial chromosomal errors
Embryos with “low-level mosaicism” — when to consider transfer
Best practices to prevent misdiagnosis: lab controls, validation, parallel assays
Role of replication / validation testing in ambiguous cases
How to counsel clinicians about residual risk despite “euploid” calls
Learning Deliverables:
Case examples: mosaic embryo reports and transfer decision
Flowchart: decision tree for borderline / mosaic results
Quiz: list three sources of false positives
Objective: To assess how well being labeled “euploid” predicts embryo viability, implantation, and healthy live birth.
Content / Key Points:
Definition of “euploid” in the PGT context
Metrics: implantation rate, ongoing pregnancy rate, live birth rate among euploid embryos
Comparative outcomes: euploid vs untested embryos, stratified by age
Limits to predictive power: non-genetic causes of implantation failure (endometrium, uterine anatomy, immunologic factors)
Mosaicism beyond biopsy: undetected mosaic changes deeper in embryo
Embryo competence beyond chromosomal architecture (mitochondrial health, epigenetics, metabolism)
Statistical caveats: cohort effect, selection bias, lab effect
Clinical interpretation: success probabilities vs certainty
Learning Deliverables:
Table: published implantation / live birth rates from euploid embryos
Example scenario: patient with multiple euploid embryos — how to counsel expectations
Quiz: what non-chromosomal factors may lead a euploid embryo to fail to implant?
Objective: To outline, in step-wise detail, the workflow, technical methods, and logistical considerations of PGT-A in an IVF / surrogacy program.
Content / Key Points:
Integration of PGT-A into the IVF / surrogacy timeline
Ovarian stimulation & retrieval
Fertilization / embryo culture
Embryo development to blastocyst stage
Biopsy (trophectoderm) at Day 5/6
Sample preparation, labeling, and shipping
Genetic laboratory analysis (e.g. NGS, array CGH, SNP arrays)
Report generation & interpretation
Embryo vitrification / cryopreservation
Transfer planning in subsequent cycle
Biopsy technical details: number of cells, technique (laser, mechanical), timing
Sample quality control: amplification, DNA quality, dropout, mosaic cell detection
Genetic assay options:
• Array comparative genomic hybridization (aCGH)
• Single-nucleotide polymorphism (SNP) arrays
• Next-generation sequencing (NGS) / low-pass whole genome sequencing
• qPCR / targeted methods
Turnaround times, cost drivers, lab accreditation / QC standards
Logistical challenges in surrogacy contexts: transporting biopsied samples, cross-lab compatibility, chain of custody
Workflow optimizations, backup plans for assay failure, retesting policies
Learning Deliverables:
Workflow diagram: PGT-A process from retrieval to transfer
Comparison table: advantages / disadvantages of different assay platforms
Case exercise: troubleshooting failed amplification in a sample
Quiz: name key QC steps in sample processing
Objective: To offer expert-level tips, caveats, and strategic considerations to optimize use of PGT-A in real-world practice (especially in surrogacy / donor cycles).
Content / Pro Tips:
Always validate your lab’s assay sensitivity, specificity, and mosaic detection thresholds
Work with genetic lab partners that have strong QA/QC and accreditation
Use internal controls and replicate runs for ambiguous calls
Maintain clean chain-of-custody protocols especially in cross-country surrogacy transfers
When embryo numbers are low, weigh the added cost vs benefit of testing
Be cautious in interpreting mosaic calls — low-level mosaic embryos may still lead to healthy live birth
Use ranking algorithms (e.g. “top euploid first”) rather than binary discard-only approaches
For donor egg or donor embryo cycles, PGT-A adds less relative value if donor is young
Stay updated with non-invasive PGT developments (e.g. spent embryo media cell-free DNA)
Maintain close liaison between embryology, genetics, clinical, and surrogacy coordination teams
Document data within your program (outcomes vs PGT classification) to refine thresholds over time
In counseling, always present residual risks and uncertainties even with “euploid” embryos
Monitor literature for new definitions, reporting standards, and mosaic classification consensus
Our job is to listen, to connect the dots between your needs, and to determine how we can best help you have your baby. If you’re asking how much does it cost for a surrogate, we’ll walk you through every step of the process to ensure there are no surprises.
To make an appointment with one of our counselors or physicians, please call (212) 661-7673 or email info@surrogacy4all.com. We look forward to hearing from you.
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