Biochemical pregnancy 8 days or a little bit of bleeding, observation after a few days did not continue to bleed generally not a big problem, after a few days of persistent bleeding may be the uterus contraction, tissue residue, uterine cavity infection and other reasons. 1. not a big problem: biochemical pregnancy is the sperm and egg to form a fertilized egg, but did not succeed in the uterine cavity and abortion, usually bleeding 3-7 days clean, the 8th day there is still a little bit of bleeding to observe, and after that there is no problem to continue to bleed. 2. poor uterine contraction: biochemical pregnancy 8 days and a little bit of bleeding, after that will continue to bleed to consider the uterine contraction, uterine contraction ability is relatively poor, the small blood vessels can not be completely closed triggered by vaginal bleeding. 3. tissue residue: biochemical pregnancy although there is no formation of the gestational sac, but the endometrium by the hormonal effects of metaplasia will occur, the endometrium will be thick, the metaplasia is not intact from the uterine cavity, part of the residual in the uterine cavity affects the uterus to repair, but also in the biochemical pregnancy after 8 days of continued bleeding. 4. Uterine infection: bleeding during biochemical pregnancy without diligent replacement of sanitary napkins, do not pay attention to perineal hygiene, may lead to the invasion of pathogenic bacteria and triggered by uterine infections, the endometrium can not be successfully repaired will lead to prolonged bleeding time. Bio-chemical pregnancy 8 days will still have a little bleeding, persistent bleeding is recommended to consult a doctor in time.