BOISE - The Idaho Supreme Court has upheld the conviction of an Idaho woman who was charged with drug possession after blood from her newborn child's umbilical cord tested positive for methadone.

In the ruling handed down Tuesday, the unanimous high court said there was probable cause to support the possession charge even though the drug had already been ingested at the time it was discovered by authorities.

According to the ruling, Sidney Neal went to a hospital in Meridian in 2011 to give birth to a baby girl, and told health care workers while she was being admitted that she had been taking prescribed oxycodone and hydrocodone for a painful medical condition. When the newborn baby showed signs of opiate withdrawal, authorities sent the umbilical cord for drug testing, which they said confirmed the presence of methadone.

Neal was charged with possession of methadone and the next year entered a guilty plea, but reserved the right to appeal the legitimacy of the charge itself.

In her appeal to the Idaho Supreme Court, Neal's attorney argued that there wasn't enough evidence to establish probable cause that she had possessed methadone because "the mere presence of a controlled substance in a person's body does not constitute possession within the meaning of criminal statutes," according to the ruling.

A positive drug test alone isn't enough to prove that someone knowingly and consciously possessed and consumed a drug, her attorney, Deputy State Appellate Public Defender Justin Curtis, told the high court.

In response, Deputy Attorney General Jessica Lorello contended that Neal has a "fairly significant addiction to opiates" and that suggested that any ingestion of methadone was done knowingly and intentionally.

Fourth District Judge Michael Wetherell wrote that the presence of methadone in the umbilical cord, along with Neal's admission that she didn't have a prescription for methadone, was enough to indicate "that Ms. Neal, at least at some point, possessed methadone without a valid prescription."

The unanimous high court concluded that the prosecution in the case was correct, agreeing that prosecutors weren't charging Neal with possession of methadone in the umbilical cord. Rather, the high court found, prosecutors used the evidence of drugs in her umbilical cord to properly show Neal possessed the drug at the time she ingested it.

"Because the state did not contend that defendant was possessing the methadone while it was in the umbilical cord, we need not address the issue of whether one is in possession of a drug after injecting, smoking, or consuming it," Justice Daniel Eismann wrote for the court.