Can a women have implantation bleeding same day as expected period?

If that is about the time when the embryo implants than yes. Implantation bleeding is rarer then what is expected. As well it is mostly a little spotting not a full out period. So if you are getting some period like symptoms then chances are it is a period. It has been known for some women to have period like bleeding events during their pregnancy as well but it is rare.

Why do you ask this?