A 65-year-old woman from Berlin is reportedly pregnant with quadruplets, German media reported on 12 April.

The woman, Annegret Raunigk, already has 13 children and the latest pregnancy follows her attempts at artificial insemination over the last year and a half.

A Russian and English teacher by profession, Raunigk, started trying for another child after her nine-year-old insisted on having a younger brother or sister, said German broadcaster RTL.

The pregnancy has reportedly gone smoothly so far, without any major complications. The babies are due in the summer.

The birth is set to make Raunigk the world's oldest mother of quadruplets. Her oldest daughter is reportedly 44.

"After the doctor discovered there were four, I had to give it some thought to begin with," Bild am Sonntag newspaper quoted Raunigk as saying.

"On the scan it was just clear to see. Certainly that was a shock for me."

Despite Raunigk never having considered the option of reducing the number of fertilised embryos, she revealed she was shocked by the news initially.

"I'm not actually afraid. I simply assume I'll remain healthy and fit. In matters of organisation I have enough experience, that's not new for me. How does one have to be at 65? One must apparently always fit some cliches which I find rather tiring," said Raunigk.

"I think, one must decide that for oneself."

The expectant mother is a grandmother to seven children as well.

Her gynaecologist, Kai Hertwig, was quoted by RTL as saying that quadruple pregnancies are always a strain, but everything is going well for Raunigk.

Hertwig said the greatest risk with quadruple pregnancies is for the babies being born prematurely and doctors are attempting to prevent that in this case.

"At first, I only wanted one child," said Raunigk. "Not all were planned. But then things happen. I'm not a planner, but rather spontaneous. And children keep me young."

Raunigk will be featured in an interview on the TV channel on the evening of 13 April.