ST. CHARLES COUNTY, Mo. – When Sherri Lohnstein arrived at the hospital in labor, she was drunk, police said. Her baby girl, who weighed just 2 pounds and had a blood alcohol content that would be twice the legal limit for an adult, died a short time later.

Prosecutors charged Lohnstein, 33, on Wednesday with involuntary manslaughter.

“I was drinking, and she died,” Lohnstein told police. “I don’t know why, but I should not have drank.”

When baby Zreanna was born Sept. 9, it was not the first time Lohnstein had been drunk, police said. She drank throughout her pregnancy against the advice of her physician, police said. Lohnstein had signed a form from her doctor making her aware of the risks associated with drinking and pregnancy, according to court records.

Police also said someone had sneaked a bottle of vodka into Lohnstein’s room at St. Joseph Hospital West in Lake Saint Louis while she was recovering from the birth.

Hospital staff contacted police, who began to investigate.

Medical records obtained by police indicate that Lohnstein had a blood alcohol level of 0.18 percent, and her baby wasn’t far behind at 0.17 percent. The legal limit for driving drunk in Missouri and Illinois is 0.08.

Charges in these types of cases are rare but have happened across the country.

An autopsy conducted by Dr. Mary Case, St. Charles County medical examiner, determined that the baby’s death was caused by acute intoxication.

St. Charles County Prosecutor Jack Banas called the case “a sad set of circumstances.”

He provided few details about Lohnstein’s background, saying only that she has several children, but he did not know whether they were in her custody.

He declined to say whether the woman had been investigated previously by the Division of Children and Family Services. He also didn’t know whether the baby was full-term when it was born.