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5 Common Misconceptions About PGS and PGD You Need to Know

To help clear the air surrounding these preventative measures, here are five common misconceptions (and little-known facts) about PGS and PGD testing:
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Patient waiting for gynaecological examination, low section
Patient waiting for gynaecological examination, low section

Your doctors tell you one thing, your family and friends tell you another. And let's not forget what Dr. Google has to say. In an age of information overload -- an age where everyone's an expert -- it can sometimes be difficult to distinguish fact from fiction.

When it comes to infertility treatments, this couldn't be more true.

I am one of the countless number of women who has had to seek out evidence, research contradictory advice, and debunk misconceptions in an effort to find infertility treatment options that best suited my personal needs. In the four years I've spent trying to have a baby, I've had four miscarriages, seven IVF transfers, three IVF egg retrievals, and lost twins during delivery. As you can probably imagine, I've just about tried it all.

Of the widely debated and misunderstood treatment options for infertility, genetic screening is at the top of the list. Preimplantation genetic screening (PGS) and preimplantation genetic diagnosis (PGD) are screening processes designed to increase the chances of a healthy embryo implantation. PGS screens for extra or missing copies of chromosomes, while PGD looks for single-gene defects that may lead to genetic disorders.

To help clear the air surrounding these preventative measures, here are five common misconceptions (and little-known facts) about PGS and PGD testing:

Misconception #1: PGS is designed for women of advanced maternal age.

It's easy to understand why so many people believe PGS is geared solely toward women of advanced maternal age. While it's true that an increase in age results in an increased risk for fertility issues, the belief that younger women aren't at risk just isn't true.

Fact: Women of all ages are at risk of having chromosomally abnormal embryos -- even women under 30 years of age. Melissa Maisenbacher, a genetic counselor at Natera, explains in an interview that with Day 5 testing, for women under the age of 30, there's a 30 percent risk for each embryo to be abnormal. For women in their late 30s, that number jumps to a whopping 50 percent.

Misconception #2: PGS is only for identifying chromosome abnormalities.

There's no denying that PGS can provide infertile couples with valuable genetic insight. By looking for chromosomal abnormalities, couples can identify and prepare for conditions like Down's syndrome.

Couples who have a family history or are at risk of chromosome abnormality are ideal candidates for PGS, but so are couples that have had multiple failed pregnancies or IVF transfers and simply want to find out why.

Fact: Preimplantation genetic screening can also be used to help infertile couples learn the reasoning behind their infertility. Most people don't know why their embryos either aren't implanting or are resulting in early losses until after genetic testing. Especially for couples dealing with unexplained infertility, PGS can supply some much-needed answers.

There are some who believe PGS is used for gender selection, or so-called "family balancing," but most fertility clinics do not share the gender with patients until they are successfully pregnant following a transfer -- and for good reason. I am glad to be under the care of a clinic that operates this way.

Misconception #3: PGD is "like playing God."

Preimplantation genetic diagnosis is considered by some to be a controversial procedure. PGD is used in conjunction with in vitro fertilization (IVF) to screen for single-cell gene defects that could lead to genetic disorders.

By screening for these genetic conditions, couples affected by an inherited disorder can reduce the risk that their children will also be affected -- hence why so many liken the procedure to "playing God."

Fact: This one isn't so black and white, as it plays on other factors, such as faith and morals. However, it's important to remember that so much of what has come about from today's medical technology can be subjected to the same interpretation, from preventative medications to C-sections to ventilators.

Misconception #4: PGD is recommended for individual carriers of single-gene disorders.

For individuals with a family history of single-gene disorders like cystic fibrosis or sickle cell anemia, PGD might seem like the obvious solution. But you may want to think twice before spending an arm and a leg on PGD to assess embryo risk.

Fact: According to Maisenbacher, most couples are not at risk for single-gene disorders. Most individuals are actually carriers of four to six different genetic diseases, but their partner is not usually a carrier for the same genetic disease. And, in the case of most single-gene disorders that PGD is done for, both parents need to be carriers in order for their to be a risk to the child.

Misconception #5: A low grade embryo results in an unsuccessful pregnancy.

IVF embryos are "graded" to help pick the best for transfer. While it might seem obvious to shoot for mostly grade A embryos, low grade embryos also have the potential to result in a successful pregnancy.

Fact: While there seems to be a relationship between embryo grade and chromosome abnormality, the two don't necessarily correlate.

"We've seen couples transfer really low grade embryos and have a successful pregnancy after knowing that that embryo was chromosomally normal when," says Maisenbacher, "if they hadn't gone through the PGS screening, that wouldn't have been one of the embryos considered for transfer based on the grade."

What do you think? What are some other misconceptions about PGS and PGD testing? Share in the comments!

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