Bleeding on the 40th day of pregnancy can be caused by miscarriage, ectopic pregnancy and cervical lesions. 1. Pre-eclampsia: 40 days pregnant a bit of bleeding may be pre-eclampsia caused by, such as during pregnancy have sex, do heavy labor work, the body of the progesterone value is low and so on, the occurrence of pre-eclampsia may have a small amount of vaginal bleeding performance, pre-eclampsia can go to the hospital to check the cause, such as the value of progesterone value caused by low progesterone supplementation treatment. 2. Ectopic pregnancy: 40 days pregnant with a little bleeding may be caused by ectopic pregnancy, the gestational sac did not normally bed in the uterine cavity, the more common is to bed in the fallopian tube pot belly. With the increase of gestational weeks and the gradual development of the embryo, the rupture of the pregnancy site may cause bleeding, the initial bleeding is relatively small, and then there may be a relatively large amount of bleeding. After the diagnosis of ectopic pregnancy, it is necessary to terminate the pregnancy in time, such as methotrexate conservative treatment or tubal opening surgery. 3. Cervical lesions: 40 days pregnant with cervicitis, cervical polyps and other diseases, the cervix is stimulated by inflammation or superfluous organisms by activities, there may be a small amount of bleeding performance, through anti-inflammatory drugs or surgical excision treatment. There are many reasons for bleeding on the 40th day of pregnancy, so it is recommended that you go to the hospital for a checkup and targeted treatment. In addition, the specific use of the above drugs should be under the guidance of a doctor.