The unnamed Tunisian woman is said to be an Arabic language teacher. She has had two miscarriages since her marriage to a colleague in 2007 and is now excited.
"All I want to do is to be able to hug my babies and show them all my love," she told hospital workers in the town of Gafsa, about 250 miles south of Tunis.
"In the beginning, we thought that my wife would give birth to twins, but more foetuses were discovered. Our joy increased with the growing number. The medical team told us that my wife would give birth naturally," said Marwan, the woman's husband.
But fertility experts have condemned the news, alleging the doctors who treated the couple are "irresponsible" and risking the health and lives of the mother and her babies.
It is not known what fertility treatment the woman had, but her husband was quoted by local papers as saying they had been expecting twins, British newspapers reported.
But Simon Fisher, a fertility expert from the University of Oxford, said the news of the duodecaplets was "horrendous" and said the doctors involved were "irresponsible" to allow it.
He said the pregnancy could have been achieved either because the couple ignored the advice of doctors and had intercourse during their treatment, conceiving naturally as well as through IVF, or religious reasons required all the embryos to have been used rather than some being destroyed.
"Whatever the reasons behind this, the chances of there being a happy ending are pretty remote," he said.
"The chances of all of them surviving are extremely remote and the chance of some of them surviving without any problems is unlikely - they are likely to have significant problems.
"Her chances of surviving depend on how well she is monitored. It will be a tremendous strain on her even if she is young and fit. IVF is practised responsibly all over the world and no one should ever get into this situation."
No one is thought to have ever given birth to 12 babies before.
In January, American Nadya Suleman gave birth to the world's longest surviving octuplets, conceived through IVF. For a while she seemed to be thriving in her new found celebrity status, but the stress of it all telling on her, she is remorseful.
In a documentary due to be screened in the United States this week, Ms Suleman, 33, a divorcee, expressed regret at her record-breaking childbirth.
She said: "I screwed myself, I screwed up my life, I screwed up my kids' lives . . . What was I thinking?"
She made the remarks while sitting on her bed, surrounded by the eight screaming babies as she attempted to feed them.
In May this year, Nuala Conway gave birth to Britain's first sextuplets for a quarter of a century.
The 29-year-old first-time mother of County Tyrone, Northern Ireland, said she conceived naturally with husband Austin Conway.
The four daughters and two sons were delivered by Caesarean section and were 14 weeks premature. But one of them died last month.