BALTIMORE (AP) _ A woman who shook her 13-day-old son so violently that he died must spend just over a year in prison after pleading guilty to involuntary manslaughter.

Carol L. Aust, 22, pleaded guilty Monday as part of an agreement in which first-degree murder charges against her were dropped.

She was sentenced to eight years in prison, but Baltimore County Circuit Judge William Nickerson suspended all but two years and credited her with the time served since her arrest in August. That left 15 months on her sentence, to be followed by three years on probation.

The boy, John Wesley Manning, died Aug. 1. An autopsy found he had bleeding in the brain caused by torn blood vessels.

Prosecutor Mike Pulver said Ms. Aust became upset because her boyfriend wasn't around after the baby was born, and took out her frustrations by shaking the boy.

''She obviously didn't want the baby dead,'' Pulver said.