The U.S. attorney’s office says 22-year-old Chelsea Nixon fell asleep while bottle-feeding her child on Aug. 18, 2018, and her shoulder ended up covering the child’s face. The child died of asphyxiation.

Authorities say Nixon had been using methamphetamine and had stayed up late the prior evening.

Nixon pleaded guilty on Feb. 7 to involuntary manslaughter and was recently sentenced to 13 months in prison.