Alpha-fetoprotein (AFP) is a glycoprotein normally produced by a developing fetus. Regarding Alpha Fetoprotein TRUE statement is:

This glycoprotein is synthesized early in gestation by the fetal yolk sac and later by the fetal gastrointestinal tract and liver. Its concentration increases steadily in both fetal serum and amniotic fluid until 13 weeks, after which, levels rapidly decrease. Conversely, AFP is found in steadily increasing quantities in maternal serum after 12 weeks. Half-life is 5-7 days. An elevated level of AFP suggests the presence of either primary liver cancer or a germ cell tumor of the ovary or testicle. Other conditions which cause elevated AFP are, gastric cancer, cirrhosis, hepatic necrosis, acute hepatitis, chronic active hepatitis, ataxia-telangiectasia, Wiskott-Aldrich syndrome. Ref: Cunningham F.G., Leveno K.J., Bloom S.L., Hauth J.C., Rouse D.J., Spong C.Y. (2010). Chapter 13. Prenatal Diagnosis and Fetal Therapy. In F.G. Cunningham, K.J. Leveno, S.L. Bloom, J.C. Hauth, D.J. Rouse, C.Y. Spong (Eds), Williams Obstetrics, 23e.