In terms of pregnancy and genetics, one of the most common topics of discussion is chromosome abnormalities.  As discussed in genetics 101, chromosomes are found in each of our cells, and along the chromosomes are  genes or instructions that tell our bodies how to grow and function.  As humans we typically have 46 chromosomes or 23 pairs, with one of each from the pair inherited from mom and one inherited from dad.

Part of the reason that chromosome abnormalities are discussed during pregnancy is simply because they are a subset of genetic conditions for which many screening and diagnostic tests have been developed.  Since there is testing available, a conversation ensues.

Historically, chromosome abnormalities, specifically those involving an extra chromosome (trisomies) like Down syndrome were discussed when mom was 35 or older at delivery.  Some of you may be thinking…

 Why 35? 

and

How much does my age matter?   

Today, chromosome abnormalities are often discussed regardless of mom’s age.  No matter how old you are, you may be wondering…

 What are the chances of chromosome abnormalities like Down syndrome based on my age?

or

How does a baby get Down syndrome or other trisomies? 

Whether you are planning a pregnancy or currently pregnant, one thing to keep in mind is that most babies are born with the typical number of chromosomes, regardless of mom’s age.  And, in general, only 3-4% of babies are born with any type of birth defect.  So, although at times it can feel like there is a lot of focus put on what might come up, the bottom line is that odds are your baby is developing just as usual.