The heats for the Women's 100m Breaststroke race at the 2009 World Championships took place on Monday, 27 July (prelims and semifinals) and Tuesday 28 July (final) at the Foro Italico in Rome, Italy.
The existing records at the start of the swim were:
References
Swimming at the 2009 World Aquatics Championships – Women's 100 metre breaststroke Wikipedia(Text) CC BY-SA