Two sisters aged just three and four were left alone with their dead mother for two days.
Officers were called to the property in Merseyside when neighbours saw the girls' legs dangling out of an upstairs window.
Emergency crews found the body of Debbie Caldwell, 29, at the house in Albert Street, Wallasey, on Sunday afternoon.
Ms Caldwell's daughters have now been handed over to social services, police said.
A Merseyside Police spokesman said the cause of Ms Caldwell's death was not yet known.
He said: "The results of the post-mortem tests are inconclusive and the cause of death of the 29-year-old woman is unascertained pending toxicology results.
"It is believed that she died on Friday. The formal identification of the woman will take place later.
"Her two children, aged three and four, who were in the house, have been referred to social services."
It is understood Ms Caldwell had lived alone with her children at the house for about 18 months.
A floral tribute left on her doorstep read: "RIP Deb. Goodnight and God bless."
