McLean, Va. ? A 5-week-old baby, whose brain-dead mother had been kept on life support for three months to allow the child to be born, died Monday after undergoing emergency surgery.

Susan Anne Catherine Torres, who was born about 13 weeks premature, died of heart failure at Children’s National Medical Center in Washington after surgeons tried to repair a perforated intestine, a family statement said.

The infant’s condition had deteriorated rapidly over the weekend, the family said. The baby’s prematurity led to an intestinal disorder and an infection that overwhelmed her body, the hospital said.

Susan Rollin Torres, a 26-year-old researcher at the National Institutes of Health, suffered a stroke in May after melanoma spread to her brain. She died a day after giving birth when she was taken off life support.

“After the efforts of this summer to bring her into the world, this is obviously a devastating loss for the Torres and Rollin families,” Justin Torres, the woman’s brother-in-law, said in the e-mailed statement.

“We wish to thank all the people who sustained us in prayer over the past 17 weeks. It was our fondest wish that we could have been able to share Susan’s homecoming with the world.”

The pregnancy became a race between the fetus’ development and the cancer that was ravaging the woman’s body. Doctors at Virginia Hospital Center in Arlington, where the baby was born, had said at the time that Torres’ health was deteriorating and that the risk of harm to the fetus finally outweighed the benefits of extending the pregnancy.

Doctors were guardedly optimistic about the baby’s chances last month, when she was born weighing less than 2 pounds. Doctors saw no signs that the cancer that spread through the mother’s body had crossed the placenta.

In late August, the family had reported that Susan had passed the 2-pound mark and had been taken off ventilators, though she stayed in neonatal intensive care.

A Web site was set up to help raise money for the family’s mounting medical bills and people from around the world had sent in more than $600,000 as of early last month. Any excess money was to be donated to cancer research and to establish a college savings plan for Susan’s brother.