A 65-year-old German schoolteacher and mother of 13 is pregnant with quadruplets and expected to give birth within the next two months, The Associated Press said based on local media reports.

Annegret Raunigk has children ranging in age from 9 to 44, from five different fathers, the newswire detailed; her latest pregnancy was not an accident but a reaction to her 9-year-old daughter's asking for a younger sibling, said the woman, who is due to retire soon.

Her gynaecologist, Kai Hertwig, was quoted by RTL television as saying that multiple pregnancies were always a strain but that in Raunigk's case, everything was in order, according to Agence France-Presse. The biggest risk for the babies is being born prematurely, but the woman's physicians are doing all they can to prevent that, the gynaecologist added.

Raunigk teaches English and Russian, and her pregnancy is the result of an artificial insemination conducted outside Germany, Focus reported. Both the egg and the sperm were donated, the local news magazine detailed.

That procedure -- illegal in Germany, where eggs may not be donated -- is common practice in other European countries such as Spain, Belgium and the Czech Republic, Stern noted. Typically, though, much younger women resort to artificial insemination, said Ulrich Hilland, who heads the Federal Association of Centers of Reproductive Medicine of Germany.

"I am not aware of any comparable cases," the gynaecologist told the news magazine. "If four embryos were knowingly implanted, that would be unprofessional because the more embryos are implanted, the higher the probability that a pregnancy of multiples will result, which in turn is linked to a higher risk," Hilland added.

Raunigk, however, vigorously defended her decision to again become pregnant, according to Bild, a German tabloid.

"How do you have to behave at 65? Evidently, you always have to comply with certain clichés, something I am fairly tired of," she said. "I think you have to decide for yourself, and -- in my opinion - you should not let others talk you into something; after all, they can do whatever they want, and I do whatever I think is right."