Alpha-fetoprotein (AFP) is a protein produced primarily by the liver and yolk sac of a fetus. In the medical world, it is often used as a marker in maternal blood screenings to identify potential genetic disorders in the fetus, such as Down Syndrome or neural tube defects. Elevated levels of AFP may indicate an increased likelihood of these conditions.

Key Takeaways

  1. Alpha-fetoprotein (AFP) is a protein produced by the liver and yolk sac of a developing fetus. High levels of AFP can be an indication of certain birth defects or other pregnancy-related conditions.
  2. A maternal serum alpha-fetoprotein (MSAFP) test is often part of routine prenatal testing. It is primarily used to check for neural tube defects, such as spina bifida, and other abnormalities including Down’s syndrome and abdominal wall defects.
  3. AFP levels can also be increased in mothers carrying multiples (twins or triplets), in premature aging of the placenta, or when the mother has a liver disorder.


Alpha-fetoprotein (AFP) is an important term in motherhood primarily because it is a protein produced by the fetus and its levels can be measured in the mother’s blood during pregnancy.

It is used as a screening tool as part of a maternal serum screening test, also known as a quad screen, in the second trimester of pregnancy.

High levels of AFP may suggest potential genetic conditions such as neural tube defects or abdominal wall defects in the fetus.

Conversely, low levels of AFP might indicate chromosomal abnormalities like Down Syndrome.

Therefore, monitoring AFP levels assists healthcare professionals in identifying potential risks or abnormalities, allowing for further diagnostic tests and early intervention if necessary.


Alpha-fetoprotein (AFP) plays a significant role in maternal health, especially during pregnancy. Basically, AFP is a protein that’s produced by the liver and yolk sac of a developing fetus. During a woman’s pregnancy, AFP crosses into the mother’s blood.

The levels of this protein in a pregnant woman’s blood can provide important information about the health and progress of her pregnancy. The primary function of AFP tests is to screen for potential defects in the fetus during pregnancy. Elevated levels of AFP may indicate defects such as spina bifida, anencephaly, and other neural tube defects.

Similarly, lower-than-normal AFP levels may suggest chromosomal disorders like Down syndrome. However, it is crucial to note that an abnormal AFP test doesn’t necessarily confirm these problems – it only indicates an increased risk. In such cases, further diagnostic tests are then conducted to either confirm or rule out these conditions.

AFP is also sometimes used in the detection of certain cancers in non-pregnant individuals.

Examples of Alpha-fetoprotein (AFP)

Prenatal Screening: During pregnancy, moms-to-be often undergo a prenatal screening test called the triple or quad screen test. This test measures levels of AFP, along with other hormones, in the mother’s blood to check for potential birth defects and conditions, such as Down syndrome or neural tube defects. Elevated levels of AFP can suggest certain conditions whereas low levels may suggest others.

Pregnancy Complications: In some real-life scenarios, a significant increase or decrease in levels of AFP during pregnancy can indicate serious complications. For example, abnormally high levels can point to neural tube defects such as spina bifida, while lower than normal levels can imply chromosomal abnormalities like Down syndrome.

Cancer Detection: AFP is also used as a tumor marker in non-pregnant individuals. In real-world contexts, doctors may order an AFP test if they suspect liver cancer or testicular cancer, as these cancers can cause the body to produce excess AFP. Hence, beyond motherhood, AFP has broader diagnostic applications as well.

FAQs for Alpha-fetoprotein (AFP)

What is Alpha-fetoprotein (AFP)?

Alpha-fetoprotein (AFP) is a protein that is produced by the liver and yolk sac of a developing baby during pregnancy. AFP levels are usually high when a baby is born and then decrease rapidly during the first year of life.

Why is the AFP test done during pregnancy?

The AFP test is a routine screening test that checks the level of alpha-fetoprotein in the mother’s blood during pregnancy. This test is used to detect certain birth defects in your baby such as neural tube defects and Down syndrome.

What does it mean if AFP levels are high?

High levels of AFP may suggest that the baby has a neural tube defect such as spina bifida or anencephaly. It can also indicate other conditions like a congenital renal problem or omphalocele. However, it’s important to remember that AFP is only a screening test and a positive result doesn’t mean that the baby definitely has a health problem.

What does it mean if AFP levels are low?

Low AFP levels may indicate that the baby has an increased risk of chromosomal abnormalities such as Down’s syndrome, Trisomy 18, or a rare genetic defect called Intrauterine growth restriction (IUGR). Again, a low AFP result doesn’t imply a definitive diagnosis and further testing is needed for confirmation.

When is the AFP test typically performed?

The AFP test, which is part of a group of tests known as a “triple” or “quad” screen, is usually performed during the second trimester of pregnancy, between weeks 15 and 20.

What should I do if my AFP levels are abnormal?

If your AFP levels are abnormal, your healthcare provider will talk with you about what the results could mean. You may be offered further diagnostic testing, such as an ultrasound or amniocentesis, to provide more information about your baby’s health.

Related Motherhood Terms

  • Prenatal Screening
  • Maternal Serum AFP
  • Spina Bifida
  • Trisomy 18
  • Gestational Age

Sources for More Information

  • Mayo Clinic – It is a trusted and highly-respected medical resource that provides information about a wide range of health topics, including Alpha-fetoprotein (AFP).
  • WebMD – This is another reliable source of medical information which may provide detailed articles on Alpha-fetoprotein (AFP).
  • American Cancer Society – Since AFP is sometimes used as a tumor marker, the American Cancer Society would have useful information about it.
  • World Health Organization (WHO) – The WHO is an international authority on health issues and may have relevant studies or reports on Alpha-fetoprotein (AFP).