Will Missing A Pill Of Clexane Affect Fracture Recovery?

hi my mum has recently come out of hospitial after breaking her leg and has been perscribed clexane everyday for the next 6 weeks or until she is mobile again, although she has polio so wasnt that mobile to begin with, i was wondering if she misses a day will it have much affect as her abdoman is very bruised and causin discomfort