GENETIC factors that affect when a woman reaches the menopause have been identified for the first time.

Scientists believe the discovery may lead to better infertility treatments.

Researchers in the Netherlands analysed genetic data from nine studies involving 10,339 menopausal women.

They found 20 single letter changes in the genetic code that were associated with having an early menopause.

The variants, known as single nucleotide polymorphisms (SNPs), were located at four different sites on chromosomes 19 and 20, two of the coiled packages of DNA that house the genes.

None of the variants had been identified before. What effect they have is unclear, but scientists suspect they influence the ovaries or the brain.

The findings were presented at the annual meeting of the European Society of Human Genetics in Vienna.

Researcher Lisette Stolk, from Erasmus University, in Rotterdam, said: “We found the 20 SNPs were all related to a slightly earlier menopause, and women who had one of them experienced menopause a year earlier than others.”

The menopause occurs when a woman’s stock of eggs, which number one or two million at birth, falls to the point where reproduction is no longer possible.

Its timing varies greatly for women, ranging between 40 and 60 years of age.