The mother of the California woman who gave birth to octuplets earlier this week says her daughter has been obsessed with having kids since she was a teenager.

Angela Suleman also said that her daughter is unmarried, and conceived all 14 of her children through in-vitro fertilization.

In an interview with The Associated Press, Suleman expressed dismay at her daughter's decision to get pregnant again last year.

"It can't go on any longer," Suleman said Friday. "She's got six children and no husband. I was brought up the traditional way. I firmly believe in marriage. But she didn't want to get married."

On Monday, 33-year-old Nadya Suleman gave birth to the octuplets at the Kaiser Permanente Bellflower Medical Center.

The babies, six boys and two girls, were delivered by Caesarian section. They weighed between one pound, eight ounces and three pounds, four ounces.

All of the babies are doing well, and are expected to remain in hospital for at least a month. Nadya Suleman may be released within a week.

While Nadya is in hospital, her mother is caring for her six other children, who are between the ages of two and seven.

However, Angela has warned her daughter that when she arrives home from the hospital, "I'm going to be gone."

The family lives in a small home in Whittier, which is about 24 kilometres east of Los Angeles.

According to her mother, Nadya had trouble conceiving and underwent in-vitro fertilization treatments to conceive her older children.

The treatments resulted in leftover frozen embryos, which Nadya did not want to destroy.

When given the option to selectively abort some of the embryos and then the fetuses, she refused, according to Angela.

However, because all of the embryos have now been used, Angela believes her daughter will not be adding to her brood.

Angela said her daughter had wanted to start a family when she was a teenager, but could not.

"Instead of becoming a kindergarten teacher or something, she started having them, but not the normal way," she said.

When she became distressed by her daughter's choices, Angela says she consulted a psychologist, who told her to throw her daughter out of the house.

"Maybe she wouldn't have had so many kids then, but she is a grown woman," Angela said. "I feel responsible and I didn't want to throw her out."

Yolanda Garcia, a former caregiver for Nadya's three-year-old autistic son, said Nadya seemed happy to have a large number of children and said she wanted a total of 12 kids.

"She told me that all of her kids were through in vitro, and I said 'Gosh, how can you afford that and go to school at the same time?"' Garcia told the Long Beach Press-Telegram. "And she said it's because she got paid for it."

Garcia was unable to provide details about how Nadya may have been paid to have children.

According to the Press-Telegram report, Nadya Suleman got a degree in child and adolescent development from California State University in Fullerton in 2006. According to a university spokesperson, Suleman was studying for a master's degree in counselling as late as last spring.

Suleman's fertility doctor has not been named, nor has the identity of the sperm donor that fathered the children been revealed.

Birth certificates for the four oldest children list a David Solomon as the father, according to The Associated Press, which did not locate certificates for the other children.