Also in Scanning and Ultrasound:
It is a blood screening test - i.e., a blood sample is taken. Two chemicals in the blood are measured and these are combined with the mothers age to give a risk category for Down's syndrome.
The results are usually back in 7 to 10 days.
If the result is in the high risk group you will be offered an amniocentesis to determine whether the baby has Down's syndrome. If the blood test shows you are at risk of Spina Bifida you will be offered a Detailed Scan.
No. If the mother has this blood test it will only detect approximately 60% of babies with Down's syndrome. Occasionally a mother put in the low risk group will have a baby affected by Down's syndrome.
This test will detect about 10% of babies with Spina Bifida.