If you go for ultrasound examination when you are pregnant, if you can’t see the gestational sac, it may be because the examination time is too early, the ultrasound examination can’t illuminate the gestational sac yet, and at the same time, it can’t be discharged due to ectopic pregnancy, biochemical pregnancy and other reasons, which need to be analyzed according to the specific situation of the patient. If the examination time is too early, the gestational sac in the uterus has not yet appeared at this time, so it cannot be seen through ultrasound examination, you can recheck the blood HCG and progesterone, if the blood HCG doubles well and the progesterone value is also good, you can continue to observe. If the blood HCG doubles well and the progesterone value is also good, you can continue to observe the pregnancy, and go to the ultrasound again after 1-2 weeks; 2. Ectopic pregnancy: the fertilized egg is laid and developed outside the uterine cavity, which is commonly seen in tubal ectopic pregnancy and, to a lesser extent, in ovarian and cervical ectopic pregnancy. In case of ectopic pregnancy, the intrauterine gestational sac will not be visible on ultrasound, but an abnormal mass may be seen in the extrauterine adnexal area. Patients can follow medical advice to observe more chorionic gonadotropin, if the doubling is not good and accompanied by tingling and bleeding in the lower abdomen, patients can follow medical advice to use mifepristone, methotrexate and other drugs to make the embryo shrink, shed and expel from the body, and can also remove thought pregnancy products through laparoscopic surgery, etc.; 3. Biochemical pregnancy: after the union of sperm and egg, the fertilized egg does not settle in the uterus, although there can be The HCG may be elevated, but the gestational sac is not visible during the ultrasound. Occasional biochemical pregnancy usually does not require treatment, but it is recommended to find out the cause of biochemical pregnancy and give targeted treatment according to the cause to prevent recurrence of biochemical pregnancy. It is recommended that patients should undergo ultrasound examinations to monitor the development of the fetus after pregnancy to rule out ectopic pregnancy and biochemical pregnancy. It is also necessary to pay attention to rest and avoid straining, and to avoid sexual intercourse in early pregnancy to prevent miscarriage.