Why didnt MLynn donate her kidney to Shelby BEFORE she had Jackson Jr, hell before she married. Wouldnt that have made her body stronger? Perhaps then she wouldnt have been so strained while giving birth and later not rejected the kidney ?
She didn't have kidney problems before having a child. That was the point. The pregnancy greatly compromised her kidneys.
People also have this fallacy that transplants are miracle-workers. They're generally better than nothing, but it wasn't like a kidney transplant sooner would have made much difference with her primary problem: brittle diabetes. It's moot anyway because her kidney function really was fine until Shelby had a pregnancy. It was the effects of terrible type-one diabetes that compromised her kidneys during pregnancy. So no, nothing could have been done before. (Except for never have a child as doctors said, but obviously she didn't want to listen to that advice.)