The study found that the percentage of girls getting their period before the age of 11 grew from 8.6% to 15.5%, and those who began menstruation before age nine more than doubled.

Girls in the U.S. are getting their first period earlier than in decades past. Researchers say there are multiple factors causing early puberty, including obesity and environmental pollutants.

Girls in the U.S. are getting their first menstrual period about 6 months earlier on average than they did in the 1950s and '60s. And the number of girls starting their period before age nine has ...

Girls have been getting their periods earlier and earlier for more than half a century. And as early onset increased, it has taken longer and longer for menstrual cycles to become regular.

A recent study indicates that girls of color, particularly Black girls, are beginning their menstrual cycles at younger ages than their peers. While the exact reasons for this phenomenon remain ...