It's not as if that's the only reason there are more kids in rural areas, but if you did move to a rural area and had a bunch of kids your children would (statistically speaking) be more likely to have sex at a younger age than children in urban areas, they'd be less likely to have comprehensive sex ed in school and more likely to have abstinence only education which means they'd be more likely to have unplanned/teen pregnancies, and I suspect they'd be less able or less likely to abort unplanned pregnancies than their urban peers as well.