Japanese researchers have discovered a protein that helps preserve chromosomes in egg cells over long periods. The finding could help explain why fertility in those who ovulate declines with age and potentially pave the way for new fertility treatments.

The research team, led by scientists from Chiba University, Kumamoto University and the Riken research institute, identified the protein — which they named OMC1 — that plays a crucial role in maintaining the bonds between chromosomes in egg cells throughout reproductive life.

The findings, published Thursday in the scientific journal Nature Aging, could provide new insights into why older people who ovulate face greater risks of infertility, miscarriage and their children having chromosomal disorders such as Down syndrome.

Unlike most cells in the human body, egg cells begin a specialized process of division, known as meiosis, during the fetal period of a person with ovaries and remain dormant after their birth until ovulation potentially decades…