NT examination does not come out may be due to improper examination time, baby does not cooperate, as well as pregnant women’s abdominal fat is too thick, abdominal distension is heavy and other reasons, the common situation is as follows: 1. Improper examination time: NT examination needs to be conducted at 11-13 weeks + 6 days, when the fetal head and hip length is between 45m-84mm, through B ultrasound measurement of the baby’s nuchal translucency layer thickness, NT thickening is associated with fetal chromosomal abnormalities and Structural malformations are associated. If the gestational week is too early or too late, NT measurement cannot be performed if the head and hip length is not within the required range; 2. The baby does not cooperate: NT examination requires the baby to be in a natural flexion position and obtain the fetal mid-sagittal section in order to complete it, and cannot be overly backward or forward flexion. At this time, pregnant women can be under the guidance of the doctor through the appropriate amount of food, appropriate activities and relaxation and other methods, such as baby in the uterus to move, change position before the examination; 3, abdominal flatulence is heavy: pregnant women have more gas in the body, a large amount of gas may press the uterus to cause interference with the examination, it is recommended that pregnant women avoid eating gas-producing food before the examination, such as flatulence can not be examined, can be appropriate to walk to promote exhaustion after the It is recommended that pregnant women avoid eating gas-producing foods before the examination, and if the examination cannot be performed due to flatulence, they can walk appropriately to promote exhaustion before the examination, or take appropriate measures as prescribed by the doctor; 4. Pregnant women should relax and avoid anxiety and tension when the above situation occurs, so as not to adversely affect the baby, which is more unfavorable to complete the examination at this time. In addition, you should choose a hospital with the best technology and equipment for the NT test to avoid unsuccessful tests due to objective reasons.