Getting prego with bf

Not criticism, but a a question. Why are some women trying to get pregnant by their boyfriend? I mean, personally I would never risk the chance of getting dumped while pregnant. The insecurity would drive me crazy. I understand that being married does not guarantee that he won't leave, but at least he was willing to commit to a marriage before trying... Maybe I'm just not part of the modern world, I mean I kind of want to wait to try again until me and the husband are more financially secure. We lost the first, but it may have been for the best, since we don't have our own house and horrid student loans!,