Having children can also provide a poor woman with status and a title within society. She isn't just a nobody, she is a Mom, and there is some respect that can come with that.
Especially true in places where women are prevented from attaining most other kinds of status and titles. There are many positive things about being a parent, but none of them can make up for not having a choice in the matter. For people who choose to have kids though, most of them don't regret that decision.