It's different for everyone. I lost mine for weeks. But if it has blood in it you need to.go.to hospital as this could be a sign thingss re starting v soon..we gr told in the UK if we have blood in it to.go.in ASAP
It could be hours or even weeks its not something to go off, how long av you been 4cm for as i keep having contractions then they stop & im 3cm so i was just wondering i$ you have bin dialated long or not?