AFP testing is usually part of triple marker. This screening exam also tests your
levels of:
- human chorionic gonadotropin (HCG)
- estriol, which is a hormone produced by your placenta and your baby’s liver
- inhibin A, which is a hormone produced by your placenta
The AFP test is especially important for women who are at high risk of having children
with birth defects, including women:
- who are 35 or older
- with a family history of birth defects
- who used harmful medications or drugs during their pregnancies
- who have diabetes
Too much or too little AFP in a mother's blood may be sign of a birth defect or
other condition. These include:
- A neural tube defect, a serious condition that causes abnormal development of a
developing baby's brain and/or spine
- Down syndrome, a genetic disorder that causes intellectual disabilities and developmental
delays
- Twins or multiple births, because more than one baby is producing AFP
- Miscalculation of due date, because AFP levels change during pregnancy
What do the test results mean?
If your results show higher than normal AFP levels, it may mean your baby has a
neural tube defect such as spina bifida, a condition in which the bones of the spine
don't close around the spinal cord, or anencephaly, a condition in which the brain
does not develop properly.
If your results show lower than normal AFP levels, it may mean your baby has a genetic
disorder such as Down syndrome, a condition that causes intellectual and developmental
problems.
If your AFP levels are not normal, it doesn't necessarily mean there is a problem
with your baby. It may mean you are having more than one baby or that your due date
is wrong. You may also get a false-positive result. That means your results show
a problem, but your baby is healthy. If your results show a higher or lower than
normal level of AFP, you will likely get more tests to help make a diagnosis.