Understanding Genetic Testing in IVF

“About half of all miscarriages are caused by chromosomal abnormalities.” I was shocked when our IVF specialist told us. Fifty per cent felt enormous. But then he added, “We can test your embryos and only transfer the ones without abnormalities.” Now he had my full attention.

By this point, we were meeting our second IVF specialist in Australia. After multiple failed and cancelled transfers – due to my thin endometrium lining – we needed another opinion. During that appointment, he laid out the reality: thin linings are uncommon, often genetic, difficult to treat, and our best chance of having a child was through gestational surrogacy. It was a lot to absorb.

Then he introduced Preimplantation Genetic Testing (PGT-A). And he didn’t mince words: “I don’t treat patients who refuse genetic testing. So it’s your choice whether you want to continue seeing me.” He immediately explained what PGT-A is and why he considers it essential. Within minutes, we were convinced.

Here is an overview:

What is Preimplantation Genetic Testing (PGT-A)?

PGT-A is a laboratory technique used to examine the chromosomes inside an embryo. A healthy embryo has 23 pairs of chromosomes – 46 in total – half from the egg and half from the sperm. When an embryo has too many or too few chromosomes, IVF transfers are more likely to fail, and pregnancies are more likely to end in miscarriage.

By identifying embryos with the correct number of chromosomes, PGT-A helps select the embryo with the highest chance of resulting in a successful pregnancy. Many clinics now consider it standard practice, and research suggests it can increase live birth rates per transfer while reducing miscarriage risk. Although anyone can choose PGT-A, it’s especially recommended for women over 35, as chromosomal abnormalities become more common with age.

Can PGT-A reveal gender?

Yes. Embryos with XX chromosomes are female; those with XY are male. However, whether you’re allowed to know the gender depends on where your embryos are created. In our case, even though our surrogacy transfers were in the United States, our embryos were created in Australia – where revealing embryo sex is illegal. The same restrictions apply in Canada and the UK. In contrast, gender selection is legal in some countries, including the USA, where it has become increasingly popular.

PGT-M: Screening for specific genetic conditions

PGT-M is less common than PGT-A and is used when there’s a known risk of passing on a particular genetic disorder. It screens for single-gene conditions such as cystic fibrosis or Huntington’s disease. In total, PGT-M can detect more than 350 genetic diseases, both common and rare.

PGT-SR: Testing for structural chromosome rearrangements

The third type of genetic testing is PGT-SR, sometimes called PGD. This test looks for structural rearrangements in chromosomes. Some people have the correct number of chromosomes but arranged differently. While they may be healthy themselves, they can pass on unbalanced chromosome patterns to their children, increasing the risk of miscarriage or developmental challenges.

Why many patients choose genetic testing

For us, choosing PGT-A brought a sense of control during a time when so much felt uncertain. After three devastating pregnancy losses, knowing there was a way to reduce the risk of miscarriage offered real comfort. And transferring only euploid (chromosomally normal) embryos gave us renewed hope.

Looking back, I can’t imagine how much time, money, and emotional energy we might have lost if we had continued transferring embryos that had no chance of becoming a healthy pregnancy. Infertility takes so much out of your hands – but genetic testing is one area where you can make a choice that may improve your odds of success.