Non-invasive means non-invasive prenatal DNA testing, fetal NT thickening, it is useful to do non-invasive prenatal DNA testing.
NT, or nuchal translucency, is the thickness of fluid accumulation in the subcutaneous tissue fluid at the back of the fetal neck, and it is one of the effective indicators for screening fetal abnormalities during early pregnancy, and it is generally more meaningful to screen at 11~13⁺⁶ weeks of gestation.
The normal value of NT is usually less than 2 mm, and greater than or equal to 2.5 mm is considered abnormal. thickening of NT increases the risk of aneuploidy, other birth defects, and subsequent death, and generally the thicker the NT, the higher the risk of fetal anomalies. Once an abnormal NT is detected during pregnancy, non-invasive prenatal DNA testing is recommended.
The principle of non-invasive prenatal DNA testing is based on the presence of fetal free DNA in maternal plasma. Sequencing of free DNA fragments (including fetal free DNA) in maternal peripheral plasma and bioinformatics analysis are performed to derive the risk rate of fetal development of trisomy 21-trisomy, trisomy 18-trisomy, and trisomy 13-trisomy, and thus to predict the risk of fetal development of these three syndromes.
Fetal NT thickening is useful for non-invasive prenatal DNA testing. If the result suggests a high risk, further prenatal diagnosis, such as amniocentesis and chorionic villus aspiration sampling, is needed. Pregnant women are advised to improve their prenatal checkups during pregnancy under the guidance of their doctors, taking into account their medical history, gestational week, ultrasound results, etc., so as to achieve eugenic fertility.