Causes of NT value thickening in test tube infants
The NT value thickening of test tube baby means that the fetal neck transparent vertical thickness (NT) is found to exceed the normal range by ultrasonic examination during prenatal screening of pregnant women. Thickening of NT value may be a manifestation of fetal development problems, or an indicator of chromosomal abnormalities. In the following four aspects, the reasons for the thickening of NT value in IVF are described in detail.
1. Chromosome abnormalities
NT value thickening is an important manifestation of chromosome abnormalities. Chromosome abnormalities can lead to abnormal development of embryos, including abnormal number and structure of chromosomes. A common chromosomal abnormality is Down syndrome, which is due to the presence of an additional chromosome 21 in the embryo. Experiments have proved that NT values of patients with Down syndrome are generally high. In addition to Down's syndrome, NT thickening may also be an indicator of other chromosomal abnormalities, including Edwards syndrome and mental retardation.
Chromosome abnormalities may be caused by genetic mutation in early embryonic development, abnormal structure of chromosomes or abnormal number of chromosomes. This abnormality often leads to embryonic development problems, leading to NT value thickening.
2. Cardiovascular malformation
Thickening of NT may also be related to fetal cardiovascular malformations. Cardiovascular malformation refers to the abnormal development of fetal heart and blood vessels, including ventricular septal defect, aortic isthmus stenosis, etc. These abnormalities will lead to fetal heart overload, which will lead to abnormal heart function, and then lead to problems in blood circulation.
There is a close relationship between fetal cardiovascular malformation and NT thickening. Due to the existence of cardiovascular malformations and abnormal lymph circulation of the fetus, the lymph in the neck of the fetus cannot be discharged normally in the broad neck region of the fetus, so the transparent vertical thickness of the neck is thickened during ultrasonic examination.
3. Hyperthyroidism
Hyperthyroidism is a disease of hyperthyroidism, which is common in pregnant women. Hyperthyroidism can lead to high levels of thyroid hormone in pregnant women, and then affect the development of the fetus. Thyroid hormone plays an important role in the process of fetal growth and development, and excessive thyroid hormone level will have adverse effects on the fetus.
Fetuses with hyperthyroidism often have neck effusion and NT value thickening. This is because hyperthyroidism causes the acceleration of blood circulation and metabolic rate of pregnant women, which leads to poor elimination of fetal metabolites in the uterus, causing neck edema and NT value thickening.
4. Genetic factors
NT value thickening may also be related to genetic factors. Some studies have shown that there are some gene mutations during embryonic development, such as gene polymorphism, which will affect the measurement of NT value. This means that even if the fetus itself does not have chromosome abnormalities or developmental abnormalities, gene mutations may also cause NT value thickening.
The mechanism of NT value thickening caused by genetic factors is not completely clear, but studies have shown that some genes are related to embryonic development and cardiovascular system development. These gene mutations may lead to abnormal development of the cardiovascular system, thus causing fetal neck effusion and NT value thickening.
Summary
Thickening of NT value in IVF may be the result of multiple factors such as chromosome abnormality, cardiovascular malformation, hyperthyroidism and genetic factors. These factors will have a negative impact on the development of embryos, leading to the accumulation of cervical lymph and the formation of NT value thickening. The NT value thickening found in prenatal screening can not only help early detection of fetal abnormalities, but also help guide pregnant women to accept further prenatal diagnosis and treatment.
