May Double Rate of Successful Implantation
Preimplantation Genetic Screening and Diagnosis (PGS/PGD) are types of genetic tests to determine if an embryo carries extra or missing chromosomes and/or inherited diseases, such as Cystic Fibrosis. PGS/PGD tests greatly reduce the chance of miscarriage and of having a child with an aneuploidy or a genetic disease of concern.
Preimplantation Genetic Screening (PGS)
- 24-Chromosome Screening: PGS screens for the number of chromosomes in one or a few cells from each embryo of an IVF cycle. Embryos with the normal number of chromosomes (46) have a better chance of implanting and creating a healthy pregnancy. After PGS screening, these embryos can be selected for transfer to the mother's uterus.
Preimplantation Genetic Diagnosis (PGD)
- Single Gene Testing: Available for couples identified to be at risk for having a child with a specific genetic disorder, PGD can test embryos for a specific, single gene mutation, so unaffected embryos can then be chosen for transfer. Spectrum's Single Gene PGD testing is done concurrently with 24-Chromosome PGS on a single embryo sample. Most genetic disorders can be tested if the gene mutations have already been identified in the patient and/or partner.
- Translocation and Inversion Testing: A person who carries a balanced chromosomal rearrangement may have an increased risk of passing on too little or too much genetic information to the embryo, possibly causing infertility, miscarriage, or birth defects and disabilities. Embryos can be tested for extra or missing chromosome pieces, and those with normal or balanced chromosome results are selected for transfer to the uterus.
Clinically Effective PGS/PGD
Spectrum PGS/PGD can increase the chance of success by identifying embryo(s) most likely to result in a healthy pregnancy. Spectrum can determine chromosome copy number, and detect unbalanced rearrangements and/or inherited diseases in an embryo.
Spectrum's key features, include:
- 24-chromosome aneuploidy screening
- Explicitly computes and reports individual chromosome confidence calls, typically >99% accurate
- Determines parental origin of aneuploidy
- Detects DNA contamination
- Corrects for the most common source of PGD misdiagnosis (allele dropout of ADO)
- Single gene PGD testing includes simultaneous 24-chromosome screening
- Screens for abnormal results due to haploidy, triploidy and UPD
(while identifying contamination and confirming parentage)
Who Can Benefit from Spectrum?
IVF patients can improve their chances for a healthy pregnancy when utilizing PGS/PGD, especially for the following indications:
- Advanced maternal age
- Single embryo transfer
- Recurrent pregnancy loss
- Prior child/pregnancy with a chromosomal abnormality
It can also be used to help:
- Maximize a donor cycle
- Determine status of frozen embryos
- Decrease the chance of a chromosomal abnormality in an ongoing pregnancy
Ask your doctor if Spectrum is right for you.
Frequently Ask Questions
Why use Spectrum preimplantation genetic screening (PGS) versus other testing technologies?
Spectrum is the most comprehensive and accurate testing technology available to screen chromosomes during PGS (also sometimes called PGD). It is based on the biological principle that all of the genetic information in an embryo comes from the egg and the sperm (biological parents). A microarray is used to scan all 24 chromosome in the cell or cells from the embryo, in addition to blood or cheek cells from both biological parents. Test results are determined by evaluating the micro array results from the embryo against the parental 'blueprint' that is created from the microarray results of the biological parents. This process has been shown to be highly accurate across all chromosomes, including the sex chromosomes, and provides more information than other testing technologies*. Results are returned within 5 business days.
*Reference: Johnson, D.S. et al. 2010 Hum Repro 25 (4):1066-1075
Is testing better for certain patients than for others?
Patients with a variety of medical histories have become pregnant using Spectrum. Studies published using other testing technologies suggest that PGS may be most beneficial in patients meeting one of the following criteria: mother over 35 years of age, history of recurrent pregnancy loss, or previous IVF implantation failure. Patients have also chosen testing to reduce the chance of having a baby with a chromosome abnormality like Down syndrome, an abnormal prenatal diagnosis result (CVS or amniocentesis), or a miscarriage due to chromosome abnormality.
What is my chance of getting pregnant after using Spectrum?
There are many different factors that influence whether or not you become pregnant during your IVF cycle. The data that Natera currently has on pregnancy rates following testing is reported by IVF centers and was not collected under a formal clinical study. These rates may change as more data is collected. On average there is a 55%-60% chance for ongoing pregnancy.
I've heard tha mosaicism is a problem with 24-chromosome PGS. What is it and what does it mean?
Mosaicism is when some of the cells of the embryo have a normal number of chromosomes, and some do not. Mosaicism creates a problem with 24-chromosome PGS, particularly for biopsies performed on Day 3, because the cell that is biopsied from the embryo and tested mau not represent the genetic make-up of the embryo as a whole. This problem is faced by all PGS technologies. However, Spectrum is unique in that it can provide information to your doctor regarding the chance of mosaicism if the results on the tested cell are abnormal. This is something you can discuss further with your doctor or the Natera Genetic Counselor after your doctor has sent in a referral.
If I do testing, what is the chance that all my embryos are abnormal and I have nothing to transfer?
Whether or not an embryo is transferred following testing depends on a number of factors including:
- Number of embryos tested
- Embryo morphology (do they develop well enough to transfer)
- Rate of chromosome abnormalities - also called aneuploidy - (influenced by maternal age and medical history)
Based on current data, women aged 35 years or younger who have eight or more embryos tested have a 99% chance of transfer of one or more embryos. For women aged 36 and older this chance is 75%. These numbers will be lower if less than eight embryos are tested or if maternal age is 40 years or older. The Natera Genetic Counselor can discuss these rates in detail with you prior to testing if you have additional questions.
I am under 35 years of age and in general good health. Won't most of my embryos have normal chromosomes?
Although the rate of chromosome abnormalities increases as women get older, aneuploidy is common in embryos regardless of the mother's age. The decision of whether or not to do PGS is something only you and your doctor can decide.
What happens if I sign up for Spectrum and have to cancel my IVF cycle or testing?
There is no cancellation fee if you cancel testing for any reason prior to shipping embryo biopsy samples to Natera.
What is a Genetic Counselor?
Natera feels it is important that patients are well informed about decisions regarding genetic testing. For this reason we have a number of Genetic Counselors on staff who have special education training in genetics and are certified by the American Board of Genetic Counseling. A Genetic Counselor is available to speak with you by phone regardless the risks, benefits, and limitations of 24-chromosome PGS plus Prenatal Support™. This is a free service that you are able to access after your doctor has sent in a testing referral (please call Natera to schedule this appointment). It is free regardless of whether you proceed with testing or not.
We are using an egg or sperm donor. Can we still do Spectrum?
Yes, in most cases. In order to do testing a biological sample (blood, cheek swab, or sperm) is required from the egg and sperm provider. If a donor is being used your IVF clinic can generally coordinate collecting this sample.
How long has Spectrum been in use?
Spectrum has been used in thousands of patients. Testing was first available to patients at the end of 2008 in a handful of leading IVF centers, and became more widely available across the US and internationally in the second half of 2009. Before offering testing to patients, an extensive pre-clinical validation study was conducted using the Parental Support technology utilized in the Spectrum test to prove that is was accurate and comprehensive. The results of this study have been published in a leading medical journal*.
*Reference: Johnson, D.S. et al. 2010 Hum Repro 25 (4):1066-1075
How do I get the Spectrum test?
If your IVF clinic currently offers Spectrum, all you need to do is ask your doctor to submit a testing referral request to Natera. Both partners need to provide blood samples to Natera by the time of embryo biopsy. Alternatively, a cheek swab sample can be submitted prior to egg retrieval. Samples can be collected using a Natera collection kit either at your IVF center or at your home. This collection kit will include all the information and paperwork you need for testing, or you can contact Natera by phone to start this process.