Bellflower, Calif. ? Newborn octuplets in Southern California are a feisty bunch that appear healthy even at nine weeks premature, a doctor said Tuesday.

Three babies are being given oxygen but appeared to be doing well, said Dr. Mandhir Gupta, a neonatologist at Kaiser Permanente Bellflower Medical Center. Two of the newborns were initially on ventilators but no longer need them.

At least four were ready for their first oral feeding Tuesday night.

“All babies were delivered vigorous, crying, kicking. Everyone was very excited,” said Dr. Karen E. Maples, chief of service for obstetrics and gynecology and the physician who personally delivered Baby No. 8.

The mother, who has not been identified, gave birth Monday to the six boys and two girls weighing between 1 pound, 8 ounces, and 3 pounds, 4 ounces. She was resting comfortably Tuesday and was elated at welcoming eight children to her family, Gupta said.

The eighth baby surprised the parents and doctors who had prepared to deliver seven children.

“It is quite easy to miss a baby when you’re anticipating seven,” said Dr. Harold Henry, chief of maternal and fetal medicine and one of 46 doctors, nurses and assistants who delivered the children by Caesarean section.

The babies were the second set of live octuplets born in U.S. history. No pictures of the children were released, and at the mother’s request doctors declined to reveal her name, any information about her family or whether she took fertility drugs before becoming pregnant, though outside experts said it is almost certain she did.

The babies — dubbed with the letters A through H — will probably remain in the hospital for at least two months and the mother could be released in a week.

The world’s first live octuplets were born in March 1967 in Mexico City, but all died within 14 hours, according to Encyclopedia Britannica.

The United States’ first live octuplets were born in Houston in 1998, three months premature. The tiniest died a week after the birth. The surviving siblings turned 10 in December.