The best time for NT examination during pregnancy is at twelve or three weeks. NT examination is a form of examination that can detect fetal abnormalities early, through B-ultrasound examination. If the NT value is normal, it does not mean that the fetus is not sick. However, if the NT value is high, the possibility of fetal abnormalities will be much higher. So, what causes high nt values?
Firstly, as the fetus develops, the transparent band behind the fetal neck will gradually disappear after 14 weeks of pregnancy. The normal range of NT is about three millimeters, and the results of this examination may be influenced by the fetal body fluids. If the NT value exceeds three millimeters, the fetus is more dangerous.
Secondly, if the NT value is high, the risk of fetal abnormalities will increase. If the thickness reaches six millimeters, the fetus may have Down syndrome or chromosomal diseases, but this is not a heart problem. Due to many reasons, it is necessary to cooperate with doctors to conduct a series of related tests to detect the condition.
Finally, some NT values are temporary due to the inability of lymph to flow out and accumulate in the neck to form NT thickening. When the fetus develops to around fourteen weeks, it will turn and lymphatic fluid flows from the lymphatic vessels behind the neck to the nose. However, both delay this number, leading to obvious lymphatic drainage disorders in the neck. Excessive lymphatic fluid accumulation in the neck may even form lymphatic sac tumors in mid pregnancy.
If babies with congenital heart disease usually have high NT values, this may be related to heart malformations that cause incomplete heart failure. Heart failure leads to impaired blood flow, increased venous pressure in the neck, and the accumulation of lymphatic reflux in the neck, resulting in increased NT values.
