< fertility services

Genetic Screening & Testing

Every couple who is trying to conceive should have at least one partner tested for chromosomal mutations which could lead to rare disorders.  Patients should also consider preimplantation genetic testing (PGT) if they have known hereditary disorders, multiple IVF cycle failures, or recurrent miscarriage.

At a Glance

  • Genetic defects in embryos are the main reason embryos do not implant after in-vitro fertilization
  • After preimplantation genetic testing, only embryos with normal numbers of chromosomes will be transferred
  • Genetic screening may be used for specific genetic defects which are in the family or detected on genetic carrier screen testing
  • Due to the improved implantation rate, patients may be more inclined to do a single embryo transfer, reducing the risk of twins or triplets
  • The gender of the embryo is known so patients can elect to transfer the embryo of the desired gender

What is preimplantation genetic testing (PGT) in IVF?

Preimplantation genetic testing (PGT) is divided into two main categories. The first and most common of these is PGT-A (formerly known as PGS) which tests for aneuploidy, the abnormal number of chromosomes in the genetic analysis of an embryo. If there is an incorrect amount of genetic material in an embryo, it can prevent implantation, result in miscarriage, or lead to severe and fatal birth defects, the most common of which is called trisomy-21, commonly known as Down syndrome. When embryos are identified with abnormal numbers of chromosomes, they simply are not replaced. They are discarded with the permission of the patient.

The second category of preimplantation testing called PGT-M (formerly called PGD) looks for monogenic/single gene defects. If a patient has had carrier screening or is aware from her family history that her child or children would be at risk for a disorder, then all the embryos can be screened first for aneuploidy, then for this genetic abnormality. Common situations are when both the husband and wife are known to be carriers for sickle cell disease or cystic fibrosis.

How is PGT done?

The steps to do genetic screening with PGT are below:

  1. At approximately day 5 of embryo development after IVF, the embryos, called blastocysts, have several cells removed microsurgically.
  2. The embryos are frozen.
  3. The DNA of the biopsied cells is analyzed for chromosomal errors or problematic genes. This complicated process takes at least one week.
  4. The embryos that are euploid (correct number of chromosomes) and free from genetic defects are available for transfer into the woman.
  5. The euploid embryos that are not transferred remain cryopreserved until the patient is ready to transfer them.
  6. The embryos that are not safe for transfer are discarded with the patient’s permission.

Who should consider preimplantation genetic testing (PGT) in IVF?

Patients should consider preimplantation genetic testing (PGT) if they have known hereditary disorders, multiple IVF cycle failures, or recurrent miscarriage. Also, women undergoing IVF at an advanced age should consider this testing since it is more common for their embryos to have genetic abnormalities.

Can preimplantation genetic testing predict all possible abnormalities?

There are abnormalities, such as mosaicism, which cannot be detected by preimplantation genetic screening. Mosaicism results from mitotic errors that occur after fertilization. About half of the embryos which exhibit mosaicism have normal chromosomes and the embryo and the baby can be normal. Putting mosaic embryos back has led to approximately half the normal implantation rate per embryo and the miscarriage rate is higher than normal. However, if no other embryos are available, transfer of mosaic embryos is a reasonable choice.

After preimplantation testing, do I know the gender?

Yes, after all the 23 pairs of chromosomes are tested including the sex chromosomes, the gender of embryos is identified.  You then have the liberty of selecting the gender of the embryo to be replaced if there is more than one embryo available of different genders.

Prenatal screening blood test

A safety valve after preimplantation genetic testing is the prenatal screening blood test, a noninvasive blood test to detect several major chromosomal abnormalities. The screening assay is used for singleton and twin pregnancies with a gestational age at least 10 weeks to rule out aneuploidies or abnormal chromosomal number combinations which can lead to Down syndrome, other anomalies, or miscarriages. Fetal chromosome mosaicism cannot be distinguished by that method, however. If patients have a mosaic embryo replaced, an invasive test of the pregnancy must be performed. Negative test results do not eliminate the possibility of fetal chromosomal abnormalities of other chromosomes or of tiny errors called subchromosomal abnormalities.

This test is not 100% accurate because the test results may reflect the chromosomal changes of the placenta and not the fetus. The test does not identify pregnancies at risk for open neural tube defects such as spina bifida.

Carrier screen

Every couple who is trying to conceive should have at least one partner tested for chromosomal mutations which could lead to rare disorders. The most common of these single gene recessive disorders is cystic fibrosis. This and at least 100 other disorders can be avoided in babies by doing a simple saliva test that is submitted to a laboratory. This screening is offered to everyone who is trying to conceive through our infertility practice.

We all have mutations in our chromosomes; they are part of evolution. Some mutations make us faster, smarter, and stronger, but other mutations can lead to a disease. If one of the partners is tested and has a mutation, then the other partner is tested to make sure that they do not also have this mutation. Very uncommonly, they do. In those cases, IVF with preimplantation genetic testing (PGT-M) can avoid the risk of having a baby with an uncommon serious or fatal illness.

 

Do I need a carrier screen if I have already had a healthy baby?

Yes, we recommend it. The risk of having an abnormal baby if you and your partner or donor have the same mutations is 1:4. So couples could have one or more babies which are normal and then have an affected child. A carrier screen is important for everyone to make sure that they do not have a baby with cystic fibrosis or other avoidable disorders.
I Felt Like I Was Visiting Friends
I Felt Like I Was Visiting FriendsREAD MORE
Read More
They were genuinely compassionate about our situation and listened to our concerns and opinions. His laid back personality put us at ease and was a stark contrast to the other doctors we had seen who were always rushed, condescending, and egotistical.
After Several Unsuccessful IUI Attempts at Another Specialist
After Several Unsuccessful IUI Attempts at Another SpecialistREAD MORE
Read More
Wow – what a difference they made in our infertility journey. They truly made us feel like family.
I Felt Special – Not Like Just Another Number
I Felt Special – Not Like Just Another NumberREAD MORE
Read More
Dr. Massey and his clinic gave me hope when I didn’t feel like there was any.
Patient, Compassionate, Sincere
Patient, Compassionate, SincereREAD MORE
Read More
I began this IVF process at two other clinics but never felt comfortable … This practice was much more affordable and flexible right from the start! There was no unnecessary testing and, more importantly, no long waits.
We Could Only Do IVF If It Was Affordable
We Could Only Do IVF If It Was AffordableREAD MORE
Read More
We were so blessed that our first IVF round worked! We had our little girl in April 2013. She is an amazing gift and I thank Dr. Massey and his staff for giving her to us.
Thank God, After All These Years, We Finally Found our Doctor!
Thank God, After All These Years, We Finally Found our Doctor!READ MORE
Read More
Dr. Massey was always so confident about going against all the odds we’ve had in our way to build our family. I will never forget his words: “Ok, ain’t gonna be easy BUT we are gonna make it happen.” Those words were music to our ears. Infertility sucks (we all know that!) and certainly there’s nothing else you want to hear than there’s hope and there’s always a way to make it happen.
I Dealt with Years of PCOS & Endometriosis
I Dealt with Years of PCOS & EndometriosisREAD MORE
Read More
With the sincerest gratitude, Dr. Massey and team...I THANK YOU!
The Other Clinic Told Us to Adopt
The Other Clinic Told Us to AdoptREAD MORE
Read More
A family friend encouraged us to take one last look at IVF. We knew we did not want to go back to the same doctor, so we began looking for someone new. My wife was then 37 and I was 32. We were very fortunate to find Dr. Massey's office where they offered the IVF process for almost half of what the previous doctor charged.
We Got Married Later in Life
We Got Married Later in LifeREAD MORE
Read More
I got married in my late 30s as many women do these days, never imagining that I would have fertility issues.
They Let Me Do Monitoring in My Home Town
They Let Me Do Monitoring in My Home TownREAD MORE
Read More
We were so excited and knew that this time it was going to work and it did! We now have a 5-month-old boy that we feel is our little miracle.
Personalized Care AND Low Cost!
Personalized Care AND Low Cost!READ MORE
Read More
Our son recently turned 10 months old and is happy and healthy in every way possible. We have begun the planning for our next child and look forward to working with them again.
Nine Years of Patience Brings Eduardo, Jr.
Nine Years of Patience Brings Eduardo, Jr.READ MORE
Read More
Thank you to all who have made my husband and I so happy and for taking the time to explain each step of our journey.
We Were Dealing with Male Factor Infertility
We Were Dealing with Male Factor InfertilityREAD MORE
Read More
We are so thankful to have found Dr. Massey online when we searched “low cost IVF centers” on Google. We have beautiful twins because of it! Our fertility journey began in 2005 when we started trying to conceive but knew we had some potential obstacles to deal with even though I was only 23 years old.
An Individualized Treatment Plan Was Key
An Individualized Treatment Plan Was KeyREAD MORE
Read More
Our gratitude is immeasurable. Thank you so, so much!
Single Mother by Choice
Single Mother by ChoiceREAD MORE
Read More
"On the second IVF cycle I got pregnant and now I have a beautiful little boy!"
Previous
Next

quicklinks