CANTON (AP) - A judge has agreed to postpone the trial of a woman accused of drowning a 23-month-old boy, allowing her defense lawyer more time to review autopsy reports.

Shirley Winters' trial was scheduled for Jan. 29, but St. Lawrence County Judge Hon. Jerome Richards granted the request for a six-week delay.

Winters, 49, is charged with second-degree murder in the 2006 death of 23-month-old Ryan Rivers.

Public Defender Brian Pilatzke said he asked for the postponement to have two separate autopsy reports reviewed by a defense expert.

Both autopsies - one done in Watertown immediately after the toddler's death, the other in Albany later - attributed death to asphyxiation due to drowning. But one autopsy also found traces of isopropyl alcohol, or rubbing alcohol, in Rivers' blood.

Prosecutors said Winters used the alcohol to render Rivers unconscious before drowning him at his grandparents' home, where she was staying at the time. Pilatzke said he needed an outside expert to determine the significance of the finding.

"I don't understand why two weeks before trial they say they need an expert to review the autopsy reports," Chief Assistant District Attorney Alexander Lesyk told The Watertown Daily Times.

Winters also faces a murder charge in Onondaga County, where she is accused of killing her five-month-old son in November 1980. She is scheduled to stand trial in that case beginning March 31. It was not immediately clear how the delay in St. Lawrence County would affect that case.

Winters was charged with suffocating Ronald Winters III after authorities exhumed the remains of the baby and two siblings - Colleen, 3, and 20-month-old John - killed in a 1979 fire in Jefferson County. The baby's death was originally blamed on Sudden Infant Death Syndrome.

Investigators renewed their interest in the deaths of the Winters children after the Rivers drowning. Winters remains under investigation in Jefferson County for the 1979 fire.

Since 1979, Winters has been linked to 17 fires at homes where she lived or the homes of family members. She was convicted of arson in 1997 and served eight years in state prison for burning down her late mother's home.