Girls in the U.S. are starting menstruation at younger ages, particularly among racial minorities and lower-income groups, prompting concern among scientists. Using data from over 71,000 participants, researchers found that early and very early menarche (before age 11 and 9, respectively) is becoming more common, while periods are taking longer to regularize.

The most significant contributing factor is higher childhood BMI, though stress, trauma, diet, and exposure to endocrine-disrupting chemicals also play roles. Early menarche is linked to higher risks of breast, ovarian, and endometrial cancers, heart disease, stroke, and fertility issues like PCOS due to longer estrogen exposure.

Girls and women can help manage risks by maintaining healthy lifestyles, reducing stress, and limiting chemical exposure. However, systemic change is essential. Governments must regulate harmful chemicals, promote public health initiatives, and support ongoing research to address this growing issue and protect future generations’ health.