A 33-year-old woman was charged with murder on Tuesday for throwing her newborn girl out a seventh-floor window in her boyfriend’s Bronx apartment, the authorities said.

The girl, who was found in an alleyway outside the apartment building on Monday, unconscious and unresponsive with her umbilical cord still attached, died of multiple blunt force injuries sustained in the fall, the New York City chief medical examiner, Dr. Barbara Sampson, said in a statement on Tuesday. The death was ruled a homicide, meaning that the infant was alive when she was thrown from the window.

The police said the mother, identified as Jennifer Berry of Yonkers, had been charged with second-degree murder and manslaughter. Ms. Berry, who briefly worked for New York City’s child welfare agency several years ago, was arraigned late Tuesday in Bronx Criminal Court, according to the Bronx district attorney’s office. Her case was adjourned until Oct. 5 and she was remanded to jail.

Ms. Berry, a police official said, apparently hid the final stage of her pregnancy from relatives and friends, including, it appears, her boyfriend. She told some of them that she had miscarried weeks ago. On Monday, she initially denied giving birth to the child but ultimately relented and admitted that she had delivered the baby, according to the official, who spoke on the condition of anonymity because he was not authorized to disclose details of the investigation.