Ultrasound can be done at 40 days of pregnancy, early pregnancy ultrasound is the gold standard for intrauterine pregnancy, the main purpose is to determine the development of the fetus and to exclude abnormalities such as ectopic pregnancy, trophoblastic disease, pelvic masses, etc. 1. exclude ectopic pregnancy: at 40 days of pregnancy, a round or oval gestational sac can be seen in the uterine cavity through ultrasound examination, proving intrauterine pregnancy; 2. observe the gestational sac: at this time, the gestational sac can be observed in The gestational sac can be observed clearly in the uterine cavity under the ultrasound examination, and even the fetal bud and the beating fetal heart can be seen in the gestational sac; 3. Correction of the pregnancy week: the ultrasound examination can be used to project the last menstruation and determine the expected date of delivery according to the length of the germ and the top-rump diameter. During the ultrasound examination, pregnant women need to drink water and hold urine, and can wear loose clothing to facilitate the doctor’s operation, so that they can better observe the embryo development. In addition, pregnant women in early pregnancy should pay attention to folic acid supplementation and stay away from radiation and the stimulation of toxic and harmful gases, which can effectively avoid fetal development malformations. Eat lightly, pay attention to rest, avoid overwork and strenuous exercise, and maintain a good mood. Avoid intercourse in early pregnancy to avoid stimulating contractions that can cause miscarriage and other adverse consequences.