Kim Kardashian: Long, Painful Birth ... This Placenta's Killing Me

Kim Kardashian's baby boy arrived with one big complication that has her calling the birth the "most painful experience ever."

Our Kardashian sources tell us the still nameless kid took a really long time to make his debut because Kim had something called placenta accreta. As we've reported ... it's a condition where the placenta grows too deeply into the uterus.

We're told the issue made the birth more difficult -- doctors needed 2 extra hours to deal with the placenta issues. Still, Kim managed to have a natural birth, instead of a c-section ... which is often recommended in such cases.

Kim's recovering from what she's calling a "very painful" experience, but we're told the ordeal's taken its toll on her appetite. No cravings ... just a lot of hospital oatmeal.

That's one way to drop the baby weight.