How much estrogen gets into system using vaginal estrogen. family history of breast cancer but not me. ?

Varies: Per the med insert: Premarin (conjugated estrogens) Vaginal Cream should not be used if you have unusual vaginal bleeding, have or had cancer, had a stroke or heart attack, have or had blood clots or liver problems, have a bleeding disorder, are allergic to any of its ingredients. This is due to significant absorption thru the vaginal mucosa which is dose dependent. Not the same risk for someone with family history only