Carol Ann MacGuineas, a free-lance writer for The Washington Post and other publications, died yesterday at a National Institutes of Health hospital after she lapsed into a coma Friday following a "risky" chemotherapy procedure, said an NIH spokesman.

The circumstances leading to MacGuineas' death will be formally investigated by a panel of NIH physicians, the spokesman said. An autopsy was to be performed today.

MacGuineas, a 44-year-old District resident and mother of two, was told that she had Hodgkin's disease, lymphatic cancer, last year, according to her brother, John Kalish. The disease went into remission after radiation therapy but MacGuineas recently had a relapse, according to Kalish and Dr. Saul Rosen, deputy director of the NIH Clinical Center where MacGuineas received treatment.

On Friday, MacGuineas consented to a chemotherapy procedure that required a surgeon to insert a catheter into one of her major arteries so he could inject an anticancer drug into her bloodstream, Rosen said.

During the procedure, the catheter tore the artery and MacGuineas bled profusely into her chest cavity, said Rosen. She lapsed into a coma and did not regain consciousness before her death yesterday afternoon, Rosen said. "Tears to the artery during this procedure are uncommon, but they do happen," he said. "The procedure is a risky procedure. This is a tragedy."

National Cancer Institute surgeon Steven Rosenberg, who served on the medical team in President Reagan's cancer operation in July, will oversee the "quality review" investigation into MacGuineas' death, Rosen said.

MacGuineas, a New York City native and Oberlin College graduate, had lived in the District since 1965 and specialized in travel and arts reporting. She compiled the Try It! column in the Post's Sunday magazine and wrote for the New York Times and other publications, her brother said.

In addition to her brother, MacGuineas is survived by her mother, Marie Kalish; her daughter, aged 17; and her son, 14. Her marriage ended in divorce.