The triple screen blood test is a multiple marker screening tool that is ordered for most expectant mothers. It looks for three specific items: AFP, Estriol, and hCG. Most medical providers will order this test before the 20th week of gestation. Most women will have the triple screen blood test ordered between the 16th-18th weeks of gestation.
- AFP, or alpha fetoprotein, is produced by the fetus.
- Estriol is an estrogen hormone that both the fetus and the placenta produce.
- hCG, or human chorionic gonadotropin, is produced exclusively by the placenta.
The invasive nature of this test is very minimal. A simple blood draw from the mother is all that is required to test for these three specific items. By comparing the results of the triple screen blood test to the expectant mother’s personal demographics, including race, ethnicity, environment, and age, medical providers are able to estimate the potential of an abnormality occurring during a pregnancy.
Should All Expectant Mothers Have This Test?
All women are typically offered this blood test when their pregnancy reaches the right week of gestation. Women from certain demographics, however, are encouraged to have this blood test completed than the general population. This includes women who are over the age of 35, have diabetes mellitus and use insulin, or have had a viral infection at some point during the pregnancy. Radiation and medication exposure are also considerations.
What Do My Test Results Mean?
High test results in these three critical areas can mean that there are developing conditions for the fetus that may require additional testing, surgery, or other treatment methods.
It is important to note that positive results from the triple screen blood test involve risks and do not provide a specific diagnosis.
There are many known instances where a false positive test has occurred. A positive result, however, will mean that further testing will happen to determine an accurate status of health for mother and the developing child.
For test results that show there are high levels of AFP, there is the possibility of a neural tube defect that has occurred. This may include anencephaly or spina bifida. The most common reason for elevated AFP levels, however, is a mis-dated pregnancy, so evaluating the developing baby generally occurs after this test result. An HD ultrasound is typically ordered.
For test results that show low levels of AFP and abnormal levels of Estriol and hCG, then there is the possibility of a chromosomal disorder occurring. The most common disorder is called Trisomy 21, or Down Syndrome. Other Trisomy disorders are also possible and each has its own unique set of symptoms. This occurs when a third chromosome develops with the other two as DNA is forming. Different levels of severity exist based on the completeness and prevalence of the third chromosome.
Why Is the Triple Screen Blood Test Important?
Some parents may avoid this blood test for personal or ethical reasons. For others, the results of the triple screen blood test are important because it allows them to prepare to raise a child that may have special needs. Certain surgeries and other potential interventions may also become available based on the test results that could save the life of the developing child.
There are already lifestyle changes that are planned when a pregnancy has been confirmed. This blood test also helps parents begin addressing the additional lifestyle changes that may be required. Part of this process is locating the resources they may need to help raise their child, support groups that can put them in touch with families who have gone through similar situations, or consider terminating the pregnancy altogether.
Although there are objections to pregnancy termination, certain Trisomy disorders can be particularly devastating to the developing child. Severe birth defects are known to occur. For example, according to NIH literature from 2010, only 7 confirmed cases of Trisomy 2 children have ever reached a live birth. Virtually all cases of this disorder result in a spontaneous abortion or a miscarriage.
It can be devastating to learn that there are higher risks for a pregnancy, but for many expectant mothers, having the information in-hand is better than being surprised by an issue during the birthing process. The triple screen blood test might not be right for everyone and it may not provide definitive results, but negative results do offer some security for a healthy pregnancy while positive results may offer life-saving treatment options.