Incremental Mutation Testing attempts to make mutation testing less expensive by applying it incrementally to a system as it evolves. This approach fits current trends of iterative software development with the main idea being that by carrying out mutation analysis in frequent bite-sized chunks focused on areas of the code which have changed, one can build confidence in the adequacy of a test suite incrementally. Yet this depends on how precisely one can characterise the effects of a change to a program. The original technique uses a naïve approach whereby changes are characterised only by syntactic changes. In this paper we propose bolstering incremental mutation testing by using control flow analysis to identify semantic repercussions which a syntactic change will have on a system. Our initial results based on two case studies demonstrate that numerous relevant mutants which would have otherwise not been considered using the naïve approach, are now being generated. However, the cost of identifying these mutants is significant when compared to the naïve approach, although it remains advantageous when compared to traditional mutation testing so long as the increment is sufficiently small.