As far as I know, there is no ICAO or Jepp reference-- it is up to what your company works out with your regulator.
At my present employer we add a 50' buffer to the MDA for protection during the go around maneuver (since the aircraft will continue descending a few feet from momentum).
However, my previous employer did not add the buffer. When I asked about it, they replied that they had discussed the issue with the regulator and it was felt that it was not necessary-- given that the location that the aircraft would reach the MDA was in the location which it would normally have continued the descent (close to the runway, with sufficient terrain clearance). I was satisfied with that explanation.