Yeah, poor thing. She doesn't even know who her biological father is at this point so custody of the child is up in the air.

There is all kinds of speculation about cause of death.  She had been taking that diet drug TrimSpa and lost a whole bunch of weight, but the main drug in the diet pill was "ephedrine" which has been proven to be dangerous and cause heart problems and has been banned, but not at the time she was taking it.  It's also possible that she was still taking it to lose  her baby weight.

I've also heard something about "foul play" because she was apparently awarded  millions by the courts from her late husband's estate a day or two ago.

Also, she apparently  had a private nurse travelling with her so it's possible that she was ill.

It also could be self inflicted because she has a history of depression and she has had a whole lot of stress and grief and high pressure on her for a long time now and it was only compounded with the death of her son. 

The first thing that came to my mind was drug overdose because whenever I've seen her on Entertainment Tonight she looks and sounds like she's stoned/high. But it could be that she was like that because of her anti-depressants.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi