The mod is not designed to treat "pregnant" or "naked" as a tags, only alternate directories to "bodies". In order for them to work, they must be located in the "bodiespreg" or "bodiesnaked" folders provided by the mod and they must have identical relative paths inside of their top level folder("bodies", "bodiespreg", or "bodiesnaked"). For example:
.../bodies/Human/Female/Teen/Black SkinL TitsH AssB [f688dac6].png
.../bodiespreg/Human/Female/Teen/Black SkinL TitsH AssB [f688dac6].png
.../bodiesnaked/Human/Female/Teen/Black SkinL TitsH AssB [f688dac6].png