The definition of biochemical pregnancy: Biochemical pregnancy refers to the union of sperm and egg, usually the sperm and egg will secrete chorionic gonadotropin after seven days of union, and after another seven days, it can be detected by the early pregnancy test. This is clinically defined as a biochemical pregnancy. Biochemical pregnancy is a category of early pregnancy and miscarriage. The main causes of biochemical pregnancy are poorly developed embryos, chromosomal abnormalities or poor uterine fertility conditions. This is more common in some women undergoing IVF. However, most women ignore it as a delayed menstruation because they did not go to the hospital for examination and they do not care about it themselves, but in fact it is already a spontaneous miscarriage. Do not be alarmed if a woman of age encounters such a situation, as it is the result of natural elimination and usually does not affect the next pregnancy. If this happens repeatedly, it is time to go to the hospital for further examination.