BTW found this interesting : FDA pregnancy category C. It is not known whether heparin will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication. Do not use heparin without telling your doctor if you are breast-feeding a baby.
And this : Overdose symptoms may include easy bruising, nosebleeds, blood in your urine or stools, black or tarry stools, or any bleeding that will not stop.
Nothing about kidney damage.
How much of an overdose did she get?
That’s a list of overdose symptoms not potential ultimate damage from overdose.
The way I read this, it sounds like the women’s life was threatened by the effects of the heparin overdose, not because of the baby. Perhaps the clot broke up into little clots and went to her kidneys and damaged them.