Girls — especially girls of color — are getting their first menstrual periods earlier

The age of a girls' first menstrual period has been decreasing among younger generations, particularly among racial minorities and lower-income populations.

Reporting on the mounting research can offer a deeper understanding of the underlying causes and broader societal impacts to females, their parents, and policymakers.

The average age of a girl's first menstrual period has dropped from 12.5 years for those born between 1950-1969 to 11.9 years for those born between 2000-2005, according to a recent study published in JAMA Pediatrics. And the time for menstrual cycles to become regular has increased, the study found.

Researchers at the Harvard T.H. Chan School of Public Health used data from the Apple Women's Health Study, with 71,341 participants reporting their age at menarche, race, and socioeconomic status. They categorized participants by birth decade and classified menarche ages as early (younger than 11 years old), very early (younger than 9), or late (ages 16 and above). A subset reported the time to menstrual cycle regularity, and another provided their body mass index at menarche.

The percentage of people who experienced early menarche increased from 8.6% to 15.5%, and the percentage of those having very early menarche more than doubled from 0.6% to 1.4%. The trends are more pronounced in girls of color, as well as girls who self-identified as low socio-economic status, the research found.

Factors such as childhood obesity, dietary patterns, psychological stress and environmental exposures may contribute to these trends​. Advocating for policies that address environmental factors contributing to early puberty, such as exposure to endocrine-disrupting chemicals, can help mitigate this trend.

Why this matters

Research suggests that the age of puberty can tell a lot about a person's long-term health.

"In general, countries with a mean age of menarche above 12 years reflect populations facing undernutrition and higher infectious disease burden; countries with ages younger than 12 years reflect populations with overnutrition and higher risk for chronic diseases," Lauren C. Houghton, Ph.D., assistant professor of epidemiology at Columbia University Mailman School of Public Health wrote in an accompanying commentary to the study.

"The U.S. is an example of the latter," she wrote.

Early onset of menstruation has been linked to a higher risk of developing breast cancer later in life. The longer exposure to estrogen over a lifetime increases this risk, and minority women already face higher mortality rates from breast cancer. Girls who mature early are more likely to become overweight or obese and develop insulin resistance, leading to an increased risk of type 2 diabetes. These conditions disproportionately affect minority populations.

Early puberty can lead to increased stress and anxiety, as young girls may not be emotionally or mentally prepared for the changes in their bodies. This stress is often compounded by social pressures and stigma. Previous studies have shown that girls who experience early puberty are more prone to depression and low self-esteem. Minority girls might face additional cultural and societal pressures, exacerbating these mental health issues.

The physical and emotional changes of early puberty can affect a girl's concentration and performance in school. This can lead to academic struggles, especially in underfunded schools that predominantly serve minority communities. Early-maturing girls may have difficulty fitting in with peers who have not yet reached puberty, leading to social isolation or association with older peer groups, which may expose them to risky behaviors.

Possible story angles

For journalists, the latest findings can provide interesting story ideas to consider.

Some schools and community organizations may be implementing health education programs in earlier grades, or they may offer a curriculum on puberty and menstruation tailored to the needs of minority girls. Empowering parents with the knowledge and resources to support their daughters through early puberty is crucial. Perhaps consider reviewing health communication materials to see whether they are culturally sensitive as parents navigate these conversations effectively.

Ensuring that girls have access to regular health check-ups can help monitor their development and address any health concerns early on. Access to mental health services is also essential. Some schools and community health centers may be offering counseling and support groups to help girls cope with the psychological impacts of early puberty.

"To address these health concerns - which our findings suggest may begin to impact more people, with disproportionate impact on already disadvantaged populations - we need much more investment in menstrual health research," corresponding author Zifan Wang, postdoctoral research fellow in Harvard Chan School's Department of Environmental Health, said in a written statement.

Increased funding for research on early puberty in minority girls can provide better insights into its causes and consequences, leading to more effective interventions, the study authors noted.

"This research can also add to the scientific evidence needed to promote higher-level interventions and policy changes that prevent exposure to harmful chemicals that disproportionately affect racially minoritized groups, which may be another factor driving the observed trends," Houghton noted in her accompanying commentary to the study.

The U.S. Food and Drug Administration policy decision to ban formaldehyde in chemical hair straightening care products is one example.

Additional resources

• National Institute of Child and Human Development
• Girls Helping Girls Period
• U.S. Department of Human Services - Office on Women's Health