Julie Corey, 39, was convicted last week of the first-degree murder of Darlene Haynes, 23, in July 2009, the Worcester Telegraph & Gazette reported.
Lawyers for Corey never disputed she was found with Haynes' baby, but argued she did not kill the victim, who was eight months' pregnant. They claimed Roberto Rodriguez, the baby's father, killed Haynes and gave the child to Corey.
Haynes was found in her Worcester apartment with skull fractures from multiple hits to the head. An electrical cord the medical examiner believed was used to strangle her was still around her neck and a 9-inch incision was found in her abdomen.
Rodriguez now has custody of the girl, who is 4 years old.