A 55-year-old woman who used in-vitro fertilization has given birth to quadruplets, The Associated Press has learned.

The three girls and one boy were delivered by Caesarean section at Mary Birch Hospital for Women last Saturday. All were in intensive care late Wednesday, one of them in critical condition.The births, first reported by television station KFMB, were confirmed to the AP by a source familiar with the situation who spoke on condition of anonymity.

The woman, who is not married, delivered the babies at 27 weeks, the source said. Their birth weights were not known.

The woman is from San Diego but went to San Francisco for the in-vitro fertilization procedure. She had been under the care of doctors at Mary Birch for several weeks. Hospital spokeswoman Jackie Hill declined comment.

In 1996, a 63-year-old woman from Highland, Calif., became the world's oldest new mom when she delivered a healthy girl after undergoing in-vitro fertilization. It took three years for her to become pregnant using a donated egg and her husband's sperm.

Last November, an Iowa couple became parents of sep-tup-lets. The seven Mc-Caugheys were conceived with the help of fertility drugs.