A little bit of blood in the early stage of pregnancy may be caused by embryo implantation, or considered to be caused by pre-miscarriage, ectopic pregnancy and other diseases. 1. Embryo implantation: As the estrogen and progesterone in the pregnant woman’s body fluctuates greatly in the early stages of pregnancy, it can stimulate the uterine lining and cause a small amount of bleeding. This kind of situation is normal, with the increase of pregnancy, its symptoms can be relieved by itself. 2. Pre-eclampsia: Pre-eclampsia may be caused by chromosomal abnormality of the embryo, serious infection of the pregnant woman, uterine malformation, endocrine abnormality and other factors. Patients may have vaginal bleeding, lower abdominal pain, back pain and other symptoms, manifested as a bit of blood in early pregnancy. 3. Ectopic pregnancy: Ectopic pregnancy may be caused by tubal inflammation, tubal dysplasia, tumor of the tissue around the fallopian tube, pelvic inflammatory disease and other factors. Patients may have abdominal pain, vaginal bleeding and other symptoms, manifested as a little blood in early pregnancy. There are many reasons that lead to a little bit of blood in the early stages of pregnancy, and it is recommended that patients go to regular hospitals and undergo relevant examinations so as to clarify the causes of the disease.