Screening And Diagnositic Testing For Down Syndrome

On the verge of becoming a first time mother I strive as we all do to make sure everything about my pregnancy was picture perfect.  I was working at the time but I still chose to exercise, with the exception of a few cravings I tried my best to eat right, I read all the books and looked at a thousand websites.  From the beginning the only glitch in my attempt for the exceptional pregnancy was the occasionally queasiness, so I never had a second thought that something could go wrong with my baby.  Then at around 14 weeks I got the standard Maternal Screening Serum that tests for different genetic markers including Down Syndrome.  I was given the option to not take this test but I knew in my heart if something were wrong I'd want to know and when my hCG level that generally indicates the increased risk for Down Syndrome came back high my pregnancy took on a whole new twist. 

Known as the "triple marker" test the Maternal Serum Screening is a test down using a sample of the mother's blood that screens the levels of serum alpha feto protein (MSAFP), chorionic gonadotropin (hCG), and unconjugated estriol (uE3).  This blood test is typically done anywhere from the 15th to 18th week of gestation, but sometimes in my case a little earlier. 

- A breakdown of the "triple marker" test:

• Alpha Feto Protein (MSAFP)- Typically if a child has Down Syndrome or is flagged for an increased risk this level will come back low.
• Unconjugated Estriol (uE3)-  These levels will also show up on the screening as low when you child likely has or is at a increased risk for Down Syndrome. 
• Chorionic Gonadotropin (hCG) - Unlike the other two levels the screening check your hCG levels will come back showing high if your unborn child is at an increased risk of Down Syndrome.

An important factor in the "triple marker" test is the gestation age of the baby.  The gestation age of the baby, the mother's age during pregnancy, and the level you tested high or low for are all factored in to create a statistical risk or probability your child will have down syndrome.  For example with my pregnancy they took my age being 23 at the time, my gestation age of 14 weeks, and finally my hCG level which came back as 3.0+ (I was told a good hCG level is less than 1.0) to determine my son's risk of having Down Syndrome was 1 in 13. 

After you get your test results from your "triple marker" screening it is important to seek a genetic counselor which is generally provided by your OBGYN should you choose to go.  With your genetic counselor you can discuss your family history of genetic birth disorders and the risks and benefits of moving forward with diagnostic testing. 

Here are a list of some different diagnostic tests for Down Syndrome after your triple marker test:

    -Amniocentesis: 

• Usually performed during the 14th to 18th week of pregnancy this test uses a needle inserted into the abdomen of the expecting mother that withdraws a small sample of the baby's amniotic fluid to examine the baby's chromosomes.  The needle is guided in conjunction with an ultrasound to keep it away from the unborn baby. Results from these test generally take around two weeks to be completed.
• Risks Factors And Side Effects Include:  Bleeding, Cramping, Infection, and leaking of the amniotic fluid afterwards.  The incidence of miscarriage is also slightly increased when this test is completed and it is generally recommended the expecting mother rest for a few days afterwards.

    -Chorionic Villus Sampling:

• In this method a small sample of the baby's placenta is collected to examine the chromosomes for the presence of Down Syndrome.  Completed during the 9th to 12th week of pregnancy the placenta can be collected in the same manner as a Amniocentesis, but can also be done through a tube placed in the mother vaginally.  Risks factors and side effects associated with this test are the same as those found with a Amniocentesis, but the possibility of miscarriage is slightly higher.

Now I want everyone to know that getting this test back with an increased risk for Down Syndrome doesn't necessarily mean you will give birth to a disabled child.  With my pregnancy my son was born with a very mild form of Down Syndrome but the "triple marker" test just means their is a increased chance that your child will have Down Syndrome.  At this point in your pregnancy they will give you options. You don't have to take them, but if you do it can give you the chance to prepare for your new bundle of joy and accept the changes that are coming into your life.  For me personally knowing didn't mean I loved my son any less, it just meant I could read up and prepare myself for the challenges I may face in the future.