Genetically Testing your Embryos

“Fifty per cent. That’s roughly how many miscarriages are due to chromosome abnormalities.” I was shocked when our IVF specialist told us this. Fifty per cent is a huge number. But then he said, “We can test your embryos and only transfer any embryos that don’t have abnormalities.” Now he had my full attention.

We were onto our second IVF specialist in Australia. After several failed, and cancelled, IVF transfers, due to my thin endometrium lining, we had decided to get a second opinion. It was at this appointment that he hit us with the hard truth: thin linings are rare, usually genetic, and often difficult to treat. And that our strongest chance of having a baby was through gestational surrogacy. It was a lot to take in. He then mentioned Preimplantation Genetic Testing (PGT-A). In fact, he was blunt, “I refuse to treat a patient who doesn’t genetically test their embryos, so it’s up to you on whether you want to continue seeing me.” He promptly explained what PGT-A is and why it’s so important. Within five minutes, he had convinced us.

What is Preimplantation Genetic Testing (PGT-A)?

It’s a scientific technique, an embryonic procedure, which looks at the chromosomes inside the cells of an embryo. A normal embryo contains 23 pairs of chromosomes, for a total of 46 chromosomes – 23 from the sperm and 23 from the egg. Embryos with more, or less, than 46 chromosomes can cause IVF transfers to fail, or can cause pregnancy loss. By identifying the best embryo for an IVF transfer, PGT-A can increase the live birth rate per IVF transfer.

Today it’s considered standard practice. Several IVF clinics worldwide offer PGT-A, also known as PGS. And for good reason. Many IVF specialists say that the chances of achieving a successful pregnancy can increase – while miscarriage can significantly decrease – with having PGT-A. And while anyone can choose to do PGT-A, it’s especially recommended for females over thirty-five years old. As a woman ages, the percentage of abnormal eggs they produce increases.

PGT-A can also screen for gender

If an embryo has XX sex chromosomes, it’s a female. If it has XY chromosomes, it’s a male. For us, selecting the gender wasn’t an option. Even though our surrogacy transfers were in the USA, through the Utah Fertility Center, our embryos were created in Australia where it’s illegal to know the gender. It’s also illegal in Canada and the UK. But it is legal in some countries like the USA, where it’s become quite popular to select the gender.

PGT-M testing

While not as common as PGT-A, PGT-M tests for gene defects. It’s usually recommended for patients who are at high risk of having a child with a specific genetic disease like cystic fibrosis and Huntington’s disease. In fact, PGT-M can screen for more than 350 common and rare genetic conditions.

PGT-SR testing

The final genetic screening test available is PGT-SR. Also known as PGD, this test screens for unbalanced chromosome rearrangements. What does this mean? Some people have the correct number of chromosomes but in a slightly different arrangement. This means they have a higher chance of passing on an unbalanced amount of chromosome information to their children which can lead to miscarriage, or the birth of a child with health and development issues.

Today, many patients are choosing to do genetic testing. I know during our infertility journey, doing PGT-A, and only transferring the euploid (normal) ones, gave us greater confidence and hope of having a successful pregnancy. And as we had suffered three heartbreaking pregnancy losses, knowing there was a way to help reduce miscarriage, was also very comforting.

I shudder to think how much time, and money, (not to mention heartache) we would have wasted if we had continued transferring abnormal embryos. With so much of infertility outside your control, it’s reassuring to know you have choice to help decrease your risk of miscarriage and increase your chance of a successful and healthy pregnancy.