The title is ironic. Despite her intense longing to be a mother, and all that she does to become a mother, Nnu Ego never experiences the "joys" of motherhood that she has been taught to expect. These joys include being taken care of in her old age, being surrounded by grandchildren, and being honored as a wife and mother. Nnu Ego struggles with infertility in her first marriage, and consequently feels like a failed woman. Not surprisingly, she is delighted when she gets pregnant immediately after marrying Nnaife, her second husband.
Child after child is born over the ensuing years, and each time Nnu Ego is grateful, until she realizes that her children are the chain around her neck. She ekes out a living through most of her life, investing in her future by paying for her children's education. But her children fail to reciprocate their mother's sacrifices, even though she does her best to set them up well in life. Because of the conclusion (see "What's Up With the Ending?"), we can assume that Nnu Ego regrets having children.
Fertility is an extremely important aspect of any African society. Children are not only an important social security system, but are also an important source of labor power. In West African societies, people are wealth and are more valuable than money or material items. Because it is difficult to clear land for farming, and because farming is essential to survival, West African societies evolved an intense need for people. The more access you had to people, the more labor power you controlled and, thus, the greater tracts of land you could successfully farm. Anthropologists use the term "big man" to describe those men in West Africa who commanded political power by accumulating the labor power of people through marriage, slavery, and having children.