From immune rejection of the fetus by the mother's body, it is the AFP that protects it. In addition, it is able to maintain the osmotic pressure of fetal blood, to participate in the organogenesis of the liver. However, until the end of the "ability" AFP doctors have not yet studied.
When pregnancy is analyzed, AFP is prescribed in order to diagnose the development of the fetus.
His level increases as the concentration of this protein increases in the blood of the embryo. Diagnosis of the fetus can be already at 12-16 weeks of pregnancy development. The maximum concentration of AFP reaches 32-34 weeks of gestation. And then it starts to gradually decrease. The level of AFP of a healthy person is reached by the first year of a baby's life.
By the end of the first trimester of pregnancy, the fetal liver becomes the main site of AFP synthesis. From there, the protein enters the bloodstream of the nascent baby, and then it is processed by the kidneys and excreted from the urine into the amniotic fluid. Together with it AFP is swallowed again by the fetus and digested. In the mother's blood, the protein enters either through diffusion, through the fetal membranes, or through the placenta or the umbilical cord.
For the first time the connection between elevated AFP levels in the pregnant woman and the presence of neural tube defects in the fetus was seen in 1972. A little later, physicians found that an increase in the level of maternal AFP is possible in cases of defects in the anterior abdominal wall of the fetus, with congenital nephroses , in general, with severe pathologies, which can lead to disability or become contraindications to life.
The association of low AFP with fetal pathologies such as Down's syndrome was discovered in 1984. At the same time, specialists established that by diagnosing the level of AFP, more than half of all cases of Down syndrome can be detected.
Gynecologists use this analysis to diagnose chromosomal abnormalities and fetal pathologies. Any deviation in development drags the increase in AFP in the mother's blood, and any deviation from the level is due to maternal obstetrics.
The best period for the study of maternal serum is 15-20 weeks of gestation. Before 15 weeks AFP is not enough to detect neural tube defects. And after 20 he already characterizes the functional degree of maturity of the fetus. It is also good to simultaneously diagnose the sera of pregnant women on both AFP and HG.
The limits of the norm for AFP are very diverse, because its level is affected also by how healthy the mother is, how her and his kidneys, liver, and cardiovascular system function.
The increased level of AFP can be caused by several reasons. May be indicative of multiple pregnancy, fetal liver necrosis, kidney pathology, umbilical hernia, developmental neural tube fetus, spina bifida, non-anterior fetal abdominal wall.
If the studies show a low AFP, then perhaps the baby has a down syndrome, a bubble skid. It can also signal a delay in the development of the fetus, its death, spontaneous miscarriage or a false pregnancy.
A somewhat lowered level of AFP may indicate an erroneously established gestation period.
In the specialized literature, medial values ??for a physiological pregnancy of a certain period and the border of the norm are often given. To assess the risk of a disease, the component is taken from the median (it is called MoM). For example, if you got 2 times higher than the medial - then 2 MoM. The more deviation from the norm, the more likely the pathology of the fetus.
2, 5 MoM means 90% probability of fetal pathology. And also neural tube defects: anencephaly, open spinal cord hernia, kidney defects.
1, 5 -2, 5 MoM - hydrocephalus, atresia of the esophagus or duodenum, chromosomal pathology.
Less than 0, 6 MoM - Down's syndrome in the fetus (if the complex is also elevated HG).
Blood is taken from the vein to determine the level of the alpha protein. Sutra is given, on an empty stomach. If there is no possibility to hand over in the morning, the blood can be collected 4-6 hours after the last meal. It is not worth while deciding on this analysis - be sure to listen to the recommendation of your doctor.
But do not panic if the study still showed a deviation in the levelAFP - in fact, this analysis is not so informative. An experienced physician can make adjustments in the study of maternal serum, taking into account the individual features of a particular organism. Often he prescribes a repeat analysis, ultrasound or additional blood donation. Ultrasound examination, for example, will eliminate obvious fetal malformations, false or multiple pregnancies.