If you had intercourse around the time of bleeding, the bleeding could have been caused by the intercourse. Remember that IB has not been medically proven. There are a number of reasons that women bleed around the implantation period that have nothing to do with implantation.
Look at it this way. The egg, when implanting, is microscopic. Something that small implanting does not cause bleeding or we would bleed with most any kind of infection.
Please read this sticky for the low down on implantation bleeding.
https://www.askmehelpdesk.com/womens...ert-53865.html