What is the probability of implantation bleeding being heavy and coming on same day expected period lasting for 4 to 5 days or it just a regular period?

The probability of implantation bleeding being heavy and coming on the same day as the expected period, lasting for 4 to 5 days, is very low. Implantation bleeding is usually lighter than a regular period and lasts for only a few hours or a couple of days. It usually occurs a few days before the expected period, not on the same day. Additionally, implantation bleeding is not as heavy as a regular period and does not last as long. Therefore, it is more likely that the bleeding you are experiencing is a regular period, not implantation bleeding. However, if you are concerned about the bleeding, it is always best to consult a doctor.