Genesis 3:1,2 tells us: Sarah lived to be a hundred and twenty-seven years old. She died at Kiriath Arba (that is, Hebron) in the land of Canaan, and Abraham went to mourn for Sarah and to weep over her. so I think she died of old age!
How Did Sarah Die In The Bible?
I think it was because of emotional shock because Abraham was going to sacrifice Isaac. I'm not sure.