The mother of a newborn baby discovered last Saturday night in a bathroom at the J.W. Marriott Hotel on Pennsylvania Avenue NW had been attending a debutante ball there and had given birth to the infant after excusing herself from the party and going to the women's restroom, according to District officials familiar with police reports in the case.

The 18-year-old Landover woman, whom officials refused to identify, left the infant in a trash container in the bathroom, where it was discovered moments later by a hotel housekeeper, who called for help, the report said. The baby girl, who weighed about 5 pounds, was reported in good condition at Children's Hospital yesterday.

The incident occurred while a debutante cotillion sponsored by the Prince George's County chapter of Links Inc., a social and service organization of black professional women, was going on in the hotel's rose-and crystal-decorated grand ballroom.

Links chapter president Gloria Massie said she had heard rumors after the party that a baby had been found in a hotel restroom. However, she added, "I don't know who the young lady [the mother] was. I don't know if she was a guest [at the Links party]. Because of that, I can't comment." She said about 500 people attended the black-tie event.

The incident began when the young woman said she wasn't feeling well and excused herself from what a city official described as a debutante ball. About 25 minutes later, her mother became concerned and went to the restroom to check on her. The young woman, who was in a stall, said she was fine, and the mother returned to the ballroom, according to the official.

A short time later, the mother returned to the bathroom looking for her daughter, but could not get in because men with walkie-talkie radios had the area blocked off, the official said. The mother was told that she could use a restroom on the next floor.

The mother, according to the official, had not been aware that her daughter was pregnant.

The mother went to the next level, where she found her daughter, who at first told her she was feeling fine and said nothing about the infant. However, before leaving the hotel, the young woman told her mother about the child, the official said.

Officials at the hotel, at 1331 Pennsylvania Avenue NW, have refused to comment on the incident.

Police spokesman Lt. William White, noting that under law details of an incident involving an abandoned child cannot be revealed, said police were called to the scene about 10:30 p.m., identified the mother and had her taken to the Washington Hospital Center, where she was admitted.

D.C. Commissioner of Social Services Audrey Rowe said the case was turned over to the city's Child Protective Services Division. It has been determined that the city will not file a neglect petition against the young woman, whose parents have asked for custody of the child.

"We anticipate the child will go home with the grandparents," Rowe said, and the division will conduct a home study to determine if the grandparents may be granted permanent custody. That decision will be made at a hearing scheduled next month in the Family Division of D.C. Superior Court.