Can you have implantation bleeding 4 days before expected period? (29 day cycle)

Yes: To be more precise, you can be pregnant and have a small amount of bleeding 4 days before you expect your period. Calling it implantation bleeding suggests we know what is happening when we really don't. Any bleeding early in pregnancy suggests a possible miscarriage, or this could simply be the start of a period earlier than you are accustomed to. A home pregnancy test would be helpful.