There is no risk to the fetus. Remember, this is only a screening test, which flags pregnancies that may need follow-up tests. It will not catch all fetuses with the above problems. An abnormal AFP level does not always mean the fetus has a birth defect. The pregnancy may be more or less advanced than estimated, or about to miscarry.
Levels are higher in pregnancies with more than one fetus.
Abnormal results occur in roughly 10 out of every 100 women tested who will be under age 35 at delivery. Women 35 are more likely to have abnormal results because the risk of Down syndrome increases with age. Because the AFP is a screening test, some women will be identified as being at increased risk even though they are carrying normal fetuses. To follow up an abnormal AFP, your clinician will probably suggest a repeat blood test, ultrasound, or amniocentesis. If follow-up tests confirm a birth defect, your clinician may refer you to a medical geneticist or other specialists.