Trends in Early Menarche and Irregular Cycles

Research reveals a concerning trend where girls are experiencing menarche at a younger age, with those born between 2000 and 2005 reaching their first period at an average age of 11.9 years compared to 12.5 years for those born between 1950 and 1969. Early periods, defined as starting before age 11, have increased from 8.6% to 15.5%, with very early periods (before age 9) rising from 0.6% to 1.4%. Additionally, the time for menstrual cycles to stabilize has increased, indicating a potential shift in maturation patterns.