- Maternal serum screening (MSS)
This screening involves measuring certain hormones called alpha-fetoprotein, human chorionic gonadotropin, with or without oestriol in the mother’s blood to determine risks.
Blood sample is taken at between 15-20 weeks of development, and a risk value is calculated in relation to the mother’s age. You are considered as screen positive if the screening test shows that the risk of Down syndrome is higher than 1 in 300.
- Non-invasive prenatal testing (NIPT)
This screening involves a single blood test and can be done as early as 10 weeks of development. In this procedure, the mother’s blood examined for fragments of the baby’s DNA to determine the chance of having Down syndrome. This screening test can have detection rates as high as 99%. These tests are usually offered by private and specialized clinics.
Important note: Being screen positive does not automatically mean that your baby has Down syndrome. It just means that there is a higher risk and you may want to consider doing further diagnostic test to confirm the condition.
If you are screen negative, you may not opt to try confirmatory diagnostic tests since the chance of your baby to have Down Syndrome is low. However, these screening tests cannot assure that the baby will be 100% healthy as some issues can still be undetected or manifest later on.