it is more than likely just her hormonal balance actin up a little it happens if she is under stress.
hi there Richie.. your wife is probably approaching the menopausal age.... so it might be hormonal changes taking place or it might be due to pregnancy as u said... or it might even be due to any other reason.. Usually implantation bleeding is spotting rather than bleeding... if bleeding persists for 5 days it's not pregnancy.. however it would be good to get it checked by a gynaec..