Nt refers to the transparent layer of the neck during pregnancy, and refers to the maximum thickness between the skin and subcutaneous soft tissue of the horizontal sagittal section of the fetal cervical vertebra. NT examination, also known as posterior cervical zona pellucida scan, is a method to measure the thickest part of the anechoic transparent layer under the skin of fetal neck by means of B-ultrasound, and is used to evaluate whether the fetus may have Down syndrome. If the pregnant woman detects that the nt value exceeds the normal range in NT examination, she should further check whether there is any abnormality, and can do amniocentesis or chorionic villus biopsy to judge whether she has Down syndrome or other diseases.
Fetuses with Down syndrome will have subcutaneous effusion, so the skin behind the neck will be thicker. If the thickness of fetal neck skin detected by NT exceeds the standard value, it may be related to abnormal fetal karyotype and other structural abnormalities. The thicker NT, the greater the probability of abnormal fetal structure and chromosome. In addition to detecting the risk of chromosomal abnormalities, the thickening of fetal neck zona pellucida is also related to congenital heart disease. If the NT test results are beyond the standard range, it is suggested that pregnant women should have a follow-up abnormal examination to further confirm the risk of fetal abnormality so as to take countermeasures as soon as possible. Nt examination is a screening method to judge whether the fetus has Down syndrome, so I think this examination is very necessary.
What examination do you do in the second trimester? First prenatal examination: pregnancy 16 weeks: analysis of the results of the first prenatal examination in the second trimester (15-20 weeks), blood pressure, weight, fundus height, abdominal circumference, fetal heart rate and Down's blood screening. Down's screening is the most important item in the second birth examination. When doing Down's screening, it is forbidden to eat and drink after 0/2 o'clock the night before/kloc-and come to the hospital on an empty stomach the next morning. In addition, the examination is also related to menstrual cycle, weight, height, accurate gestational age and gestational age. It is best to consult a doctor about other preparations before the examination.
Third check-up: 20 weeks pregnant: blood pressure, weight, fundus height, abdominal circumference, fetal heart rate, fetal malformation screened by B-ultrasound (18-24 weeks), blood routine and urine routine. The most important item of the third birth check-up is to screen fetal malformation by B-ultrasound, and to do ultrasound examination at 20 weeks of pregnancy, mainly to see if there are any major problems in fetal appearance and development. The doctor will carefully measure the fetal head circumference, abdominal circumference and thigh bone length to check whether there is any congenital abnormality in the spine. If the expectant mother does four-dimensional color Doppler ultrasound, she can also see the baby's real-time facial expression. Before doing color Doppler ultrasound, what expectant mothers need to do is to keep a peaceful mind. If they are too nervous, it will affect the activity of the fetus.