Prosecutors said Erb admitted to using drugs, including methamphetamine, before, during and after the birth of Tamberlynn, but never around the children.
Tamberlynn tested positive for marijuana at birth.
She was born premature with respiratory distress and weighed 4 pounds, 11 ounces.
She weighed 4 pounds, 6 ounces the day she died.
Investigators said they found unused government milk vouchers in the home. Erb told them she had not used the vouchers to buy formula because she had lost the code needed to redeem them.
The baby was hospitalized and received seven blood transfusions; the infant suffered liver and brain failure, according to an arrest affidavit, and was diagnosed with multiple congenital anomalies.
Prosecutors said Erb failed to follow up with doctor's visits, saying she and Wheeler used money for drugs instead of buying gas.
Wheeler, who testified at Erb's hearing, was sentenced to 25 years in prison in January 2011.