Sentence:  I realized , now , that she had been showing me , in what impressed me as being a very accurate way , something her <WSD>mother</WSD> had once said to her ; it was as if she was showing me one of the reasons why she hated that woman inside her . 
Meaning of the word marked with <WSD> tags:  a woman who has given birth to a child (also used as a term of address to your mother)