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The Role of Preimplantation Genetic Testing in IVF for Recurrent Miscarriage

Many patients seeking fertility care do so in order to treat recurrent miscarriage. Recurrent miscarriage is defined as the unintended end of two or more pregnancies before the 20th week of fetal development. At NYU Langone Fertility Center, we know how challenging recurrent miscarriage can be, which is why our team of fertility specialists and embryologists collaborate with nurses, psychologists, and wellness experts to help families who experience this condition.

The doctors at NYU Langone Fertility Center work with patients to tailor each treatment plan to their specific needs, ensuring each patient experiencing recurrent miscarriage receives the best care possible. Treatment begins with the evaluation of the patient’s overall reproductive health to determine the cause of recurrent miscarriage – from genetic abnormalities to structural issues – and from there your care team develops an individualized treatment pathway.

In many cases, recurrent miscarriage is caused by genetically abnormal embryos. For patients who have experienced multiple miscarriages due to chromosomally abnormal embryos, In Vitro Fertilization (IVF) with Preimplantation Genetic Testing (PGT) may be the best course of care. This enables our team of fertility specialists and genetic counselors to test each embryo for specific genetic and chromosomal issues that may cause miscarriage and allows your doctor to transfer only healthy, chromosomally normal embryos to the uterus, greatly reducing the chance of miscarriage.

Preimplantation Genetic Testing

Preimplantation genetic testing, formerly referred to as preimplantation genetic screening, requires that patients first undergo in vitro fertilization to create embryos. A small number of cells from the developing embryos are then removed in a process called an embryo biopsy. The biopsy is performed by skilled embryologists at NYU Langone Fertility Center. The embryos are then frozen and stored onsite at NYU Langone Fertility Center, while the sample of cells removed is sent to a genetic testing lab to perform PGT analysis.

There are 4 possible results from PGT-A testing: euploid, aneuploid, mosaic, and inconclusive.

• A euploid or “normal” result means that 23 pairs of chromosomes were detected in the embryo culture. These embryos have the highest chance of resulting in a live birth and the lowest chance of miscarriage.
• An aneuploid or “abnormal” result means that at least one chromosomal abnormality was detected in the embryo culture. NYU Langone Fertility Center does not recommend transferring aneuploid embryos, as they very rarely result in healthy pregnancies.
• A “mosaic” result means there is some risk of extra, missing, or damaged chromosomes in some, but not all, cells in the embryo culture. Embryos with mosaic results sometimes result in healthy live births, but do so at a lower rate than euploid embryos. If you are considering transfer of a mosaic embryo, NYU Langone Fertility Center requires a consultation with our genetic counselor prior to initiating a frozen embryo transfer (FET) cycle.
• Finally, an “inconclusive” result means the genetic testing laboratory was unable to obtain a clear result from the embryo culture. This occurs in approximately 2% of embryos, and does not necessarily indicate a problem with the embryo – it is simply a known limitation of testing a small amount of genetic material.

In 1992, NYU Langone Fertility Center program director Dr. James Grifo performed the first embryo biopsy that led to a live birth in the United States. Today, we perform PGT on over 75% of all embryos created during traditional IVF cycles.

The Success Rate of PGT Tested Embryos

At NYU Langone Fertility Center, our live birth rate from PGT-A screened euploid embryos exceeds 50%, regardless of female age at egg retrieval. Please note, however, that the incidence of genetic abnormality increases as women age: embryos created from eggs retrieved while a woman is in her 20’s and early 30’s have a 30-50% chance of exhibiting an abnormal result; when embryos are created from eggs retrieved after a woman reaches the age of 40, the percentage of abnormal embryos increases to 70-90%.

Next Steps

Once patients being treated for recurrent miscarriage with preimplantation genetic testing receive their results, they will discuss the quality of each embryo with their physician. This will help to determine which embryo will be selected for transfer. When the patient is ready, the patient may begin a Frozen Embryo Transfer (FET) Cycle.

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