Estriol is a steroid female sex hormone that belongs to estrogens. Doctors even call it the main estrogen of pregnancy, because estriol helps increase blood flow through the vessels of the uterus (thereby reducing their resistance), and also participates in the development of the mammary duct system. Under normal conditions, the level of estriol in the woman's body is much lower than in pregnancy. But with the birth of a new life in the womb of a woman, since the formation of the placenta, the concentration of this hormone increases significantly. The main amount of estriol during pregnancy is produced just by the placenta, later it is produced by the liver of the fetus.
Since both the placenta and the fetus participate in the formation of estriol, the analysis of this hormone in the blood serum permits to determine the possibility of the development of pathological conditions in the fetus. So, the lower the level of estriol in the blood, the greater the risk of encountering the development of pathological conditions. Threatening is considered to reduce the level of estriol more than 40%.
To measure the level of estriol in the blood, the corresponding analysis is carried out in the interval of 14 and 20 weeks. For analysis, blood from the vein is surrendered - preferably in the morning and on an empty stomach. In this case, it is worth considering that in the morning, the concentration of this hormone in the body is higher. Therefore, for serial studies (and if the analysis is not done in the morning), samples should be taken at the same time of day.
The doctor will pay special attention to the level of estriol if:
- the mother's age is more than 35 years, father - more than 45;
- There were cases of developmental defects in previous children;
- there is a family carriage of chromosomal diseases;
- there was radiation exposure to one of the parents
- pregnancy was complicated by diabetes or hypertension
- before pregnancy, a woman had an acquaintance with the regular miscarriage of the fetus
A decrease in the level of estriol in the blood is a bad indicator. Reduced estriol can provoke miscarriage or premature birth; become a symptom of Down syndrome; malformations of the central nervous system (fetal anencephaly); intrauterine infection of the fetus; congenital heart diseases. Also, a decreased level of estriol may be due to the administration of antibiotics or glucocorticoids. But increasing the values ??can be the result of liver disease, kidney failure. Also, a sharp rise in the level of estriol can occur when there is a threat of premature birth. At the same time, the level of estriol also increases in the case of multiple pregnancies or the development of a large fetus.