The Role of Genetics in Fertility

Genes are the hereditary traits passed from parent to child. More than 20,000 genes are handed down to you from your parents, spanning generations and determining traits like height, hair and eye color, and sex. Genes also determine what illnesses and conditions run in families. 

Think of your genes as part roadmap and part instruction manual. Occasionally, the roadmap contains a genetic change or mutation that can happen on its own or be inherited from the biological parent. 

How Genetics Impact Health

When a gene change occurs it can cause serious health conditions, such as sickle cell disease or cystic fibrosis. A gene change may also cause heart defects or other birth defects that may compromise how the body looks and works. Genetic birth defects may cause developmental delays and overall lifetime health problems.

Some genetic mutations affect chromosomes, resulting in a chromosomal disorder. Every person has 46 chromosomes, 23 from each biological parent. Like genes, sometimes the order or number of chromosomes changes. An extra chromosome is called trisomy and may result in a condition like Down syndrome. A missing chromosome is called monosomy and may result in a condition known as Turner syndrome. Both conditions involve physical and developmental delays. Children can inherit chromosomal changes from their parents, or the changes may occur on their own in the very early stages of embryo development. 

What is Genetic Counseling?

Genetic counseling is a way to understand your own genetic makeup, your partner’s genetic makeup, and what that means for your future child. Genetic counseling helps you uncover any risks to your pregnancy from inherited health conditions, birth defects or medical conditions present in your genes and how these conditions may affect your future baby. 

What Does Genetic Counseling Involve?

When you undergo genetic counseling, you’re working with someone who understands the role genes play in determining both the risks and the cause for such risks, that you might pass on to your children.

Some of the reasons for seeking genetic counseling are:

• You or your partner are aware of a personal genetic condition.
• You already have a child who has a genetic condition.
• You are aware of a genetic condition that runs in your or your partner’s family.
• You or your partner belong to an ethnic group predisposed to genetic conditions such as Sickle Cell disorder, Tay-Sachs disease or Thalassemia.

Your family health history is extremely valuable to your genetic counselor who will take into account any health conditions present in any of your or your partner’s biological relatives. 

Types of Genetic Testing

Below are genetic tests available to you and your partner before and after conception. 

Carrier Screening

Before conception, you and your partner can choose to undergo carrier screenings. With this test, the lab examines blood, saliva, or tissue from a cheek swab to determine if you or your partner carry certain genetic conditions and how likely you are to pass the condition on to your baby.  If you both carry a genetic predisposition for the same condition, there is a risk to your future baby. At that point, you’ll assess the risks and make decisions about becoming pregnant. 

Of course, deciding to have the screening or any of the tests, is a personal choice and one you make with your partner. 

Targeted Carrier Screening

Targeted carrier screening is highly recommended for certain conditions that run in families or ethnic groups. If your family history or ethnic makeup carries a high risk of any of the above and others listed below, you may want to consider targeted carrier screening:

• Fragile X Syndrome
• Sickle Cell Disorder
• Tay-Sachs 
• Thalassemia
• Cystic Fibrosis
• Spinal Muscular Atrophy

Preimplantation Genetic Testing (PGT)

PGT is a test available to those going through an IVF cycle. If the prior screening shows you or your partner carry a risk of a genetic abnormality, you may opt to undergo PGT after egg retrieval and fertilization. With PGT, the lab waits about five or six days until the embryo reaches the blastocyst stage when the cells are clearly defined as pre-placental and those that make up the actual embryo. The lab takes a few of the pre-placental cells to examine for any genetic or chromosomal defects that would result in birth defects, miscarriage or stillbirth. 

Once the viability of your embryos is confirmed, your doctor implants the healthiest embryo(s) in your uterus during the embryo transfer. Of course, if any of the embryos tests positive for a genetic mutation, your physician and your genetic counselor will help you understand what that means for your future child. Knowing the risks you and your family may face helps you make decisions and plan for the future. 

Let’s Navigate this Journey Together

Babies inherit a genetic makeup that is all their own, and what parents contribute affects a baby’s future. Genetic testing can help ensure a healthy future by uncovering any conditions that may affect a baby’s quality of life. For more information on genetic testing and IVF, please contact Reproductive Health and Wellness.