Why? Americans have access to free or a sliding scale healthcare, foodstamps, free housing, at least 2 meal a day for kids in school, also family planning clinics for birth control, and there are min. wage jobs in almost all towns. Why do people think they have a right to bring a child into this world if they can not support themselves 100%. I am not talking abortion. Also I am not talking about people that lost there jobs.
The primary problem is transportation; in most cases the nearest clinic (which will normally have very limited hours) is over an an hour's drive over very rough back roads, and there is no public transit unless a social worker has the time and resources to take pity on you, which doesn't happen often. Since they can't reliably get to the clinic, they don't have reliable birth control, either. Lots of these babies are born at home, and many are premature and don't make it. (Ambulance service in this area is largely run by membership co-ops; if you haven't paid your membership you would be looking at a really serious bill that you couldn't pay, and besides that, there is often no phone to call one.)
It's also a long haul to the nearest supermarket, and lots of folks don't have a working fridge and/or stove. It's not uncommon for people in the Delta to exist on a strange combination of junk food and wild food (mostly blackberries, pecans, turnip greens, crawfish and frog legs, with duck on a good day, if someone has enough ammo to shoot one.) Some people try to keep chickens, but that can be hard because they are so likely to get stolen. Diabetes and asthma are absolutely rampant around there, and so is sickle cell.
There is no subsidized housing in the rural parts of the Delta, unless you count the occasional old mobile home that gets given away. (That happened after Katrina, and then they mostly got taken back because of the formaldehyde outgassing from them.)
The dropout rate in the Delta is very high, and a lot of these babies are being born to young teen Moms. There really are no jobs around to speak of for women, especially if you don't have a vehicle at your disposal. The men mostly work on the farms or on road projects, but modern cotton and soybean farming doesn't use much manual labor, so unemployment is very high, too, except around Tunica where the casino tourism provides for a bit more prosperity.