A 65-year-old German mother of 13 is getting ready to give birth again -- this time to quadruplets.

Annegret Raunigk, a Berlin schoolteacher who is due soon to retire, is expected to give birth to the four babies within the next two months, Bild newspaper and RTL television reported.

She already has children ranging in age from 9 to 44, from five fathers. Raunigk said she decided to become pregnant again because her 9-year-old daughter wanted a younger sibling.

Her decision was met with widespread criticism by medical professionals as a risk both to her and the unborn babies.

"Any pregnancy of a woman over age 45 has to be considered a high-risk pregnancy; over 60 this is naturally extreme," Dr. Holger Stepan, head of obstetrics at the University of Leipzig, told the dpa news agency.

"The 65-year-old body is definitely not designed to carry a pregnancy, not of one child and certainly not of quadruplets," he said.

Raunigk told Bild that donated eggs were fertilized and implanted at a clinic outside Germany, which was successful only after multiple attempts.

She defended her decision: "How does one have to behave at 65?"

"They can see it how they want to," she said, "and I'll see it the way I think is right."