1. Causes of brown discharge after pregnancy It is very common to have brown discharge after pregnancy. This may be due to the following reasons: 1) early pregnancy bleeding; 2) cervicitis or cervical cancer caused by sexual intercourse. ;3) Endometriosis; 4) Miscarriage or difficulty in implantation, etc. 2. Brown discharge caused by early pregnancy bleeding In the early stages of pregnancy, the inner wall will undergo some changes, which may cause some minor bleeding.