A female’s first menstrual period, known as menarche, occurs during puberty. Menstruation indicates that the body is mature enough for reproduction. About 98% of girls begin their periods by age 15.

Menstruation is a natural biological process experienced by nearly half the global population. Yet, for many girls, the first period arrives as a surprise—often misunderstood, feared, or even ...

Girls who grow up eating a healthier diet than their peers may be less likely to get their first menstrual periods at an earlier age — regardless of height or body mass index — a new study suggests.

For girls, starting their period is inevitable. But the age when a child’s period begins, called menarche, can tell them a little about their health later in life. Menarche that begins “anytime ...