How Can Spotting Despite Having Normal Periods Be Treated?

hi, i m 28 yrs old, I hav a problem of monthly period. My last due date is 7th of Jan. Last 20th feb , i hav strated spotting problem den as usual my monthly period came from 10th of march. After 5 days over for my bleeding but stil i m facing d problem of spotting. Also we r plan 4 baby. Can u suggest me should i hav 2 consult to doc? Is it serious problem? n also ask what is the reason of dis problem?