The women in the IR file (and the men in the MR file) are de facto members of the household. That is, only the household members who have hv103=1 ("slept here last night"), and are in the correct age range, will proceed to the individual interviews. You don't have to do anything when you analyze the files. They are already limited to de facto members of the household. Note that this criterion applies to the women/mothers (and the men) but not to the children. MICS surveys are de jure. There are a few tables in the DHS reports in which the de facto criterion is applied to data collected in the household interview, in order to be consistent with MICS. Otherwise, when comparing DHS and MICS surveys, you should be aware of this difference, but in fact there is almost complete overlap in the de facto and de jure populations.