Alpha-fetoprotein is a substance of protein origin, which is produced in the yolk sac of the embryo, after birth - in the digestive tract, as well as in liver cells. Normally, it contains up to 15 ng / ml in the body.
Alpha-fetoprotein is determined during pregnancy to diagnose fetal malformations . The definition of this indicator also finds application in oncology. Alpha-fetoprotein is a tumor marker for testicular and liver cancer. In approximately 70% of men with a testicular tumor, its level rises, especially with metastasis of the process.
Initially, this protein substance is synthesized in the ovaries by the corpus luteum. In the fifth week, the fetus begins to produce it itself. Alpha-fetoprotein protects the fetus from the mother’s immune system, for which it is a foreign agent.
Its concentration increases in proportion to both the blood of the embryo and the blood of the mother. The optimal value of this indicator for diagnosis is at 12-16 weeks. At 32-34 weeks of gestation, alpha-fetoprotein reaches its maximum level. The norm of a healthy person is reached already in the first year of a child's life.
Research methods significantly affect the definition of this indicator. The common designation for deviations from the norm of the content of alpha-fetoprotein has become the multiplicity of the median (MoM). The median is the average in an ordered series of protein concentrations normal during pregnancy at this time. Thus, it is possible to compare alpha-fetoprotein during pregnancy at different periods, as well as analyzes made in different laboratories. Levels of this indicator from 0.5 to 2.5 MoM are normal.
An increase in alpha-fetoprotein may be a sign of:
- Tumors of the bronchi.
- Metastases in the liver.
- Cancer of the stomach, pancreas, lungs, liver, colon, breast.
- Germinal testicular and ovarian tumors.
Temporarily and slightly alpha-fetoprotein increases with the following pathologies:
- Cirrhosis of the liver,
- Chronic liver failure
- Chronic alcoholism with the presence of liver damage,
- Chronic or acute viral hepatitis.
This indicator is increased during pregnancy is in the following cases:
- Multiple pregnancy.
- Renal pathology in the fetus.
- Umbilical hernia in the fetus.
- Necrosis of the liver in the fetus.
- Malformations of the neural tube (rachischisis, anencephaly).
- Failure of the anterior abdominal wall of the fetus.
- Other malformations.
However, reduced alpha-fetoprotein during pregnancy may indicate the following:
- False pregnancy.
- Developmental delay.
- Death of the fetus.
- Bubble drift.
- Spontaneous abortion.
- Trisomy on the 18th or 21st chromosome.
A reduced concentration of alpha-fetoprotein may indicate an incorrect determination of the gestational age, that is, conception occurred later.
In gynecology at the present stage, this indicator is the main marker of fetal pathology and chromosomal disorders during pregnancy. Deviations from the normal development of the fetus alter the normal concentration of this protein substance in the mother’s blood. Of course, it is necessary to carry out not only the definition of this indicator, since this is uninformative. Ultrasound research is absolutely necessary, due to which it will be possible to exclude the incorrect determination of the term, multiple pregnancy and so on. It is also necessary to determine the placental hormones (chorionic gonadotropin and free estriol), allowing an accurate assessment of the fetoplacental system. Their combination with alpha-fetoprotein is determined in a triple test, which allows you to determine the risk of various malformations in the fetus.