maternal serum alpha-fetoprotein

maternal serum alpha-fetoprotein The presence of alpha-fetoprotein (AFP), a plasma protein that is normally produced by the fetus, in the mother’s blood. Abbreviated MSAFP. MSAFP serves as the basis for some valuable tests. AFP is manufactured principally in the fetus’s liver but is also found in the fetal gastrointestinal tract and in the yolk sac, a structure that is temporarily present during embryonic development. The level of AFP is typically high in the fetus’s blood, goes down in the baby’s blood after birth, and by 1 year of age is virtually undetectable. During pregnancy, AFP crosses the placenta from the fetal circulation and appears in the mother’s blood. The MSAFP can be screened to detect a number of disorders, including open neural tube defects, such as anencephaly and spina bifida, in which case MSAFP tends to be high; Down syndrome, in which case MSAFP tends to be low; and other chromosome abnormalities.