When a woman has a biochemical pregnancy, it will show the symptoms of menstrual interruption, as well as changes in blood HCG and the absence of a gestational sac on ultrasound. 1. Menstruation stops: When biochemical pregnancy occurs, sperm will combine with egg cells to form a fertilized egg, at this time, menstruation will temporarily stop, and menstruation will come back after the fertilized egg is discharged. 2. Changes in blood HCG: When biochemical pregnancy occurs, due to the formation of fertilized egg, it will cause changes in hormone levels, and the blood HCG level will increase, but after a period of time, it will decrease again. 3. Failure to see the gestational sac on ultrasound: when biochemical pregnancy occurs, the fertilized egg can be formed, but due to chromosomal abnormalities and other factors, the fertilized egg does not implant, and the presence of the gestational sac cannot be detected under ultrasound examination. There may be other manifestations of biochemical pregnancy, when a woman has a biochemical pregnancy, it is recommended to go to the hospital in time, under the guidance of the doctor to clarify the reasons for the occurrence of biochemical pregnancy, to avoid the next pregnancy biochemical pregnancy again.