By the Incinta Fertility Center Care Team · Medically reviewed by James Lin, MD, Medical Director · Fertility Clinic Torrance & South Bay, California
If you are moving forward with IVF, one of the most consequential choices you may face is whether to test your embryos genetically before transfer. Preimplantation genetic testing (PGT) can identify embryos with the wrong number of chromosomes and, in specific situations, embryos that carry a known inherited condition. It can sharpen decision-making—but it also adds cost, time, and nuance that deserve a clear explanation. This guide covers what PGT is, the three main types (PGT-A, PGT-M, and PGT-SR), how testing works, what results do and do not mean, and how to decide whether it fits your situation here in Torrance and the South Bay.
1. What Is Preimplantation Genetic Testing (PGT)?
PGT is a laboratory method for testing embryos created through IVF before they are transferred to the uterus. A trained embryologist removes a tiny sample of cells from each embryo—usually from the trophectoderm, the part of a day-5 to day-7 embryo that largely becomes the placenta—and sends those cells to a genetics laboratory for analysis. The results help you and your physician decide which embryo, if any, to transfer first.
Two framing points matter. First, PGT is an information tool, not a guarantee: it describes the biopsied cells and helps prioritize embryos, but it cannot promise pregnancy or a perfectly healthy child. Second, PGT applies only to embryos made through IVF—it is not part of IUI or other insemination treatments. If you are still deciding between IUI and IVF, our comparison guide explains which starting point fits different diagnoses.
2. Why Embryo Chromosomes Matter
Healthy human cells carry 46 chromosomes in 23 pairs; eggs and sperm each contribute 23. When an embryo ends up with an extra or missing chromosome—a condition called aneuploidy—development usually goes wrong. Aneuploidy is the leading biological cause of failed implantation and early miscarriage, and a small number of aneuploidies (such as trisomy 21, Down syndrome) can continue to a live birth.
Aneuploidy becomes more common as the egg ages. Based on population data summarized in publications from the American Society for Reproductive Medicine (ASRM) and U.S. CDC ART surveillance, typical published estimates suggest that a substantial share of embryos from women in their mid-twenties is already aneuploid, rising to a large majority by the mid-forties. These are population-level ranges, not predictions for any individual or any clinic—but they explain why embryo genetics, and age, shape IVF planning so strongly.
3. PGT-A: Screening the Number of Chromosomes
PGT-A (aneuploidy testing) checks whether an embryo has the expected 46 chromosomes—all 24 chromosome types screened. Patients and physicians consider it to:
- Prioritize the embryo with the best chance of implanting, especially when several blastocysts are available.
- Reduce miscarriage risk by avoiding the transfer of clearly aneuploid embryos, a consideration that matters more with increasing age.
- Support single-embryo transfer, lowering the risks that come with twins while keeping per-transfer odds strong.
- Provide information that helps couples and physicians plan next steps after unsuccessful cycles.
The honest counterweight: PGT-A does not improve the inherent quality of an embryo, and its benefit for younger patients with a good prognosis is debated in the literature. Professional guidance, including ASRM committee opinions, emphasizes individualized counseling rather than routine use for everyone. Section 9 covers who tends to benefit most.
4. PGT-M: Testing for a Known Single-Gene Condition
PGT-M (monogenic testing) is used when one or both partners carry a known change in a single gene that could affect a child. Common examples include cystic fibrosis, sickle cell disease, Tay-Sachs disease, Huntington disease, and hereditary cancer syndromes such as BRCA1/2. Many couples learn they are carriers through routine carrier screening before or during fertility care.
PGT-M requires a customized setup: the genetics lab builds a probe specific to your family’s mutation, which typically takes additional weeks and sometimes samples from family members. Fertilization is usually performed with ICSI to minimize sample contamination. Done properly, PGT-M can dramatically reduce the chance of passing on the specific condition—though it cannot screen for every possible genetic problem, and prenatal testing is still recommended to confirm results.
5. PGT-SR: Testing for Structural Rearrangements
PGT-SR is for a parent who carries a balanced structural chromosome rearrangement, such as a translocation or inversion. Carriers are usually healthy themselves, but when they make eggs or sperm, the chromosomes can split unevenly, producing embryos with missing or extra chromosome segments. This often shows up as recurrent miscarriage or repeated implantation failure, and it is typically discovered through a blood test called a karyotype during an infertility workup.
PGT-SR identifies which embryos inherited a balanced or normal chromosome set versus an unbalanced one, helping prioritize transfers with better potential. As with the other types, it narrows risk for the specific rearrangement tested—it is not a blanket guarantee for all chromosomes beyond that analysis.
6. How the PGT Process Works, Step by Step
PGT is layered onto a standard IVF cycle. For the full treatment overview, see our complete IVF guide for Torrance. With PGT added, the sequence typically looks like this:
- 1. Ovarian stimulation and egg retrieval — injections prompt multiple eggs to mature; eggs are collected in a short sedated procedure.
- 2. Fertilization — eggs are fertilized with sperm in the lab, often using ICSI when PGT-M is planned.
- 3. Embryo culture to blastocyst — embryos grow in the incubator for five to seven days.
- 4. Biopsy — an embryologist removes a handful of trophectoderm cells from each viable blastocyst.
- 5. Vitrification (freezing) — biopsied embryos are frozen while the cells are analyzed; frozen embryo transfer is now the standard pathway with PGT.
- 6. Genetic analysis — the genetics lab uses next-generation sequencing (NGS) or similar methods on the biopsied cells.
- 7. Results and counseling — results commonly return in about one to two weeks, and your physician reviews what they mean for your plan.
- 8. Frozen embryo transfer (FET) — a chosen embryo is thawed and transferred in a carefully prepared cycle.
A fair trade-off to know: because embryos are frozen while awaiting results, PGT requires a freeze-all approach and adds roughly two to four weeks before transfer. For most patients this has little practical downside, but it is one more reason the decision is individualized rather than automatic.
7. Understanding Your PGT-A Results
PGT-A reports generally fall into these categories:
- Euploid: the biopsied cells show the expected 46 chromosomes. These embryos are prioritized for transfer.
- Aneuploid: an extra or missing whole chromosome (or a large segment) was found. These embryos are typically not transferred.
- Mosaic: the sample shows a mix of normal and abnormal cell lines. This is an area of active research—some mosaic embryos can still lead to healthy births, though with lower odds and different considerations. Transfer of a mosaic embryo is only considered after thorough genetic counseling, and sometimes re-biopsy, so the decision is never automatic.
- No result: occasionally a sample fails analysis; the embryo usually remains frozen and can sometimes be re-biopsied.
Keep one principle in mind: results describe the few cells that were sampled, not every cell of the embryo, and not the future child. That is why a euploid result is encouraging but not a certainty, and why prenatal testing later in pregnancy remains important.
8. What PGT Can—and Cannot—Do
A balanced view of PGT starts with what the testing is actually built to do—and where its reach ends.
PGT can:
- Identify many whole-chromosome errors before transfer, so clearly aneuploid embryos are not used.
- Reduce the risk of miscarriage associated with aneuploid embryos in some groups, particularly at older ages.
- Support confident single-embryo transfer, which lowers multiple-pregnancy risk for mother and babies.
- Test for a specific inherited condition (PGT-M) or a known rearrangement (PGT-SR) within your family.
- Provide useful information for planning after failed or repeated-loss cycles.
PGT cannot:
- Guarantee pregnancy or a healthy baby—even euploid embryos sometimes fail to implant, and pregnancy always carries normal risks.
- Detect every genetic or developmental problem—no embryo test is exhaustive; small or low-level issues can be missed.
- Replace prenatal testing—NIPT, CVS, or amniocentesis later in pregnancy are still recommended to confirm.
- Fix an underlying fertility problem—PGT adds information and selection, not treatment of the cause itself.
9. Does Age Change Whether PGT Makes Sense?
Evidence and professional opinion generally support PGT-A most strongly for patients who are 35 or older, have had recurrent miscarriage, have had a prior aneuploid conception, or have experienced repeated implantation failure with good-quality embryos. In these settings, information from testing often meaningfully shapes the plan.
For younger patients with a strong prognosis and several blastocysts, the picture is more nuanced: cumulative chances of live birth can be similar with or without testing across multiple untested transfers, and PGT adds cost and freezes every batch of embryos. Guidelines from ASRM emphasize shared, individualized decision-making—not a universal recommendation. If you are not ready to try yet but want to keep options open, egg freezing plus later testing is another conversation worth having early.
10. Accuracy, Safety, and Common Concerns
Modern PGT platforms such as NGS are highly accurate for the cells tested, but no test on a small sample is perfect: mosaicism, sampling limits, and rare technical issues mean a small margin of both false-positive and false-negative results remains. This is precisely why results are interpreted in context and why prenatal confirmation is still advised.
On safety, blastocyst biopsy is performed daily in experienced embryology programs worldwide. The procedure carries a small technical risk to the embryo, and published follow-up studies of children born after trophectoderm biopsy have not shown evidence of long-term harm—though, as with all assisted reproduction, long-term surveillance continues. If your embryos are being tested, it is reasonable to ask how many biopsies your embryology team performs and what their handling protocols are. At Incinta Fertility Center, these questions are welcome at our Torrance fertility clinic.
11. Cost and Insurance Considerations in California
For planning purposes only, typical U.S. industry ranges reported publicly are roughly as follows (not quotes from Incinta—your final estimate is itemized and provided in writing at consultation):
- PGT-A lab fees: commonly about $2,000–$6,000 per IVF cycle, often structured as a batch fee plus a per-embryo charge of a few hundred dollars, depending on how many embryos are biopsied.
- Embryo biopsy fee: commonly about $1,500–$2,500 per cycle where billed separately, alongside the embryo freezing and storage fees already part of many IVF packages.
- PGT-M / PGT-SR: case-specific, typically higher than PGT-A because of custom probe development and family studies; the genetics laboratory quotes this directly after records review.
Insurance coverage for PGT varies widely—some California plans cover genetic testing when medically indicated, while others exclude it. During consultation, Incinta provides transparent written estimates and reviews financing options, so the decision can be made with real numbers rather than guesses.
12. How PGT Fits into Your IVF Timeline in Torrance
With PGT-A, expect the testing step to add roughly two to four weeks between egg retrieval and frozen embryo transfer—blastocyst development, biopsy, analysis, and cycle preparation. With PGT-M, the pre-work matters more: probe setup and family studies can take several weeks to a few months before your IVF cycle even starts, so tell your team early if family history or carrier screening suggests you may need it.
From stimulation start to transfer, many patients undergoing IVF with PGT-A complete the journey in about six to ten weeks, though every plan is individualized around your test results, cycle response, and scheduling needs. Your physician will map this timeline with you rather than forcing a fixed schedule.
13. Frequently Asked Questions
Does PGT test for everything?
No. PGT-A screens the number of chromosomes; PGT-M and PGT-SR test for a specific known gene change or rearrangement in your family. No embryo test can detect every possible genetic or developmental condition, which is why prenatal testing later in pregnancy remains recommended.
Is PGT worth it if I am under 35?
It depends. For younger patients with good prognosis, the benefit per cycle is more debated, and professional guidance favors individualized counseling. PGT-A may still make sense for specific reasons—recurrent loss, prior aneuploid pregnancy, or a preference for single-embryo transfer—so the decision is best made with your physician after reviewing your results.
What is a mosaic embryo, and can it be transferred?
A mosaic result means the biopsied cells showed both normal and abnormal cell lines. Some mosaic embryos can still lead to healthy births, but with lower expected odds and additional considerations. Transfer is only considered after detailed genetic counseling—and sometimes re-biopsy—so it is never an automatic choice.
Does a normal PGT-A result guarantee a healthy baby?
No. A euploid result meaningfully improves the odds that an embryo will implant and continue, but it does not rule out every genetic or developmental issue, and pregnancy always carries normal risks. Prenatal testing such as NIPT or amniocentesis is still recommended to confirm.
Does the biopsy damage the embryo?
Blastocyst biopsy is a well-established procedure performed in experienced programs worldwide, with a small technical risk. Published follow-up studies of children born after trophectoderm biopsy have not shown evidence of long-term harm, and research surveillance continues. Your embryology team can explain their protocols in detail.
14. Taking the Next Step
PGT is neither an obligatory add-on nor a magic filter—it is a tool whose value depends on your age, diagnosis, embryo count, and personal priorities. The most useful first step is a consultation where your history, carrier screening, and ovarian reserve testing are reviewed together, so the question becomes not “is PGT good?” but “is PGT good for you?” That is a conversation worth having in person, with your numbers on the table.
Wondering whether embryo genetic testing belongs in your plan? Schedule a consultation with our fertility specialists in Torrance to review your testing options—PGT-A, PGT-M, or PGT-SR—alongside your personalized IVF plan.
Incinta Fertility Center — Fertility Clinic Torrance & South Bay, California. Patient-first care, bilingual support, and laboratory leadership you can trust.
