A 56-year-old woman who gave birth to her triplet granddaughters said she was hoping one of the girls would be home from the hospital by Saturday.

Jaci Dalenberg, 56, of Wooster, north-east Ohio, offered herself as a surrogate when her daughter Kim Coseno and husband of three years Joe were waiting to adopt.

Mrs Coseno had two children from a previous marriage but was unable to have another baby because of a hysterectomy.

Her ovaries could produce eggs, so she and her husband tried IVF treatment. The embryos were implanted in Mrs Dalenberg's uterus.

The girls - identical twins Gabriella Claire and Carmina Ann and sister Elizabeth Jacilyn - were born by Caesarean on October 11 - more than two months premature and each weighing less than three pounds. Elizabeth is expected to be the first to go home.

Mrs Coseno told ABC's Good Morning America that the baby girls were doing well at Hillcrest Hospital in the Cleveland suburb Mayfield Heights.

A 56-year-old carrier was highly unusual, said Dr Robert Kiwi, who performed the IVF. A typical carrier is a young, healthy woman who had a baby previously.

Mrs Dalenberg underwent hormonal therapy to strengthen her uterus and delivered at 31 weeks when one of the girls appeared to not be growing appropriately, Dr Kiwi said.

"So we acted fairly rapidly based in information we had," Dr Kiwi said. "All three are doing great."