We learn very quickly in The Joys of Motherhood that a woman's role in traditional Ibo society is to produce children, and in particular, to produce male children. Her value as a woman is dependent on her fertility. If she is infertile, she is a "failed" woman. If she has only girls, she isn't a failed woman, but she lacks honor. Nnu Ego has absorbed these values, and her life's greatest wish is to be a honored woman. She has child after child, but ultimately, realizes that the rules of the game were made by men, and that her children have become a chain around her neck.
Although it may seem that the urbanized women in Lagos are less oppressed by patriarchs, traditional Ibo culture actually afforded women a great deal of independence.
Although it may seem that Western culture and values is to blame for the misery in Nnu Ego's life, it is actually her adherence to traditional values that created her problems.