There are no three lines through ultrasound at any period of pregnancy. Eleven weeks and four days is equivalent to almost three months of pregnancy, when the fetus has already developed, and a clear human form of the fetus can be seen through ultrasound, and the fetus can be observed moving inside the uterine cavity. The head and hip length of the fetus on the fourth day of the eleventh week is around 45-63 millimeters, the weight is around 14-19 grams, and the internal organs of the fetus have been formed, and swallowing movements have appeared. At this time, it is necessary to do a good NT examination, through the ultrasound to observe the thickness of the fetal nuchal translucency band, if the thickness is greater than 3 mm, the possibility of chromosomal abnormality is considered to be high, and it is recommended to do a good mid-term Down’s syndrome screening or non-invasive DNA examination. Eleven weeks and four days if the ultrasound results are abnormal, it is recommended to consult a doctor in time, with the help of the doctor to clarify the cause of the disease, and to carry out targeted treatment or therapy.