Monday, December 12, 2011

What in the heck is a triple screen anyway?

Every couple must decide on whether to ask for the triple screen at the end of the first trimester. Often, the doctors office doesn't have the time to explain what the test is all about; they had you a packet of information with an insert about it and its put away with all the other inserts. When you present for your 12-13 week appointment, they want to know if you are having the test and you are clueless. So, inthe interest of all those folks who call me for answers, here is a tutorial on the triple

There are still some "birth defects" that we cannot predict in utero. No way to determine if your child is going to develope autism, yet. Ultrasound has given us wonderful windows into in utero development that has been invaluable in detecting abnormalities in a comparitively young pregnancy. There are some tests that can be used for detecting chromosomal defects as early as twelve weeks gestation. Although studies pointing to advanced maternal age as a significant risk factor some some chromosomal abnormalies, The American College of Obstetricians and Gynecologists recommends the test to all pregnant women, regardless of their age.

The triple screen determines increased risk for trisomy 13, 18 and 21. What are these defects? What do they affect? Why is testing considered important? How is it done?
Is this the MSAFP test? If not, what is that for and how is that done? What do all these results mean. Is there anything I can do?

Trisomy 13 is caused by having an extra copy of chromosome 13; one more than a normal baby. It has a very poor prognosis with a life expectancy of under a year. These babies have mental retardation and multiple physical abnormalities which may include their heart, brain, spinal cord, eyes, extra digits, deformed mouths and weakened muscles. It is sometimes called Patau syndrome.

Trisomy 18 is called Edwards syndrome, which is caused by an extra chromosome 18. About fifty percent of babies with this syndrome are stillborn. If they live through childbirth, they face life-threatening complications that include cardiac abnormalities, deformities of hands and feet and the digestive system. Some have kidney problems and retarded growth and mental development.

Down's syndrome is trisomy 21 which is an extra copy of chromosome 21. There are more than 400,000 people in the US who have Down's problems including heart defects, mental retardation, hearing problems and leukemia and several who live independently and have a relatively normal life but usually a shorter lifespan. There is great varience from individual to individual.

Being tested for these abnormalities will give you information about your baby long before it is born. This information can help you in your planning for this pregnancy. Often you can be proactive about planning for medical care for your child even before birth.

The test includes a finger stick and an ultrsound. And results of both are used to estimate risk of these chromosomal defects. The test is accurate for trisomt 13 and 18 95% of the time. Ad accurate for Down's syndrome 91% of the time.

The MSAFP is a separate blood test to screen for open neural tube defects, like spina bifida. It tests for levels of alpha-fetopropein which when high may indicate an open nueral tube defect.

Further testing can be done to corroberate positive findings of triple screens and AFPs. CVS and amniocentesis are done by perinatologists. What is most important for you to remember is that negative findings occur 95% of the time and a negative is normal! I believe that any information that you can receive about your baby is vital for you to be able to be prepared to make all the choices you may need to consider when fetuses are positive for these syndromes and defects.