Girls Are Getting Their Periods Alarmingly Early

The number of girls getting their period very early is rising at alarming rates. Childhood obesity and endocrine-disrupting chemicals may be to blame.

The age for menarche — the first menstrual period in a female adolescent — has been decreasing in the United States and globally, sparking concerns about the impact on girls' lives.

Early menarche is associated with a higher risk of cardiovascular diseases, cancers, and premature death, while adolescents who get their first period late are at increased risk for fractures.

A new study published in JAMA Pediatrics reveals that percentages of early and very early menarche have increased by almost 2-fold.

The study used data from 71,341 U.S. female individuals born between 1950 and 2005. It found that the average age at menarche decreased from 12.5 (1.6) years from 1950 to 1969 to 11.9 (1.5) years from 2000 to 2005.

The number of individuals experiencing early menarche rose from 8.6% to 15.5%, while the number of girls experiencing very early menarche increased from 0.6% to 1.4%.

Meanwhile, the number of individuals experiencing late menarche dropped from 286 (5.5%) to 137 (1.7%).

Asian, Hispanic, non-Hispanic Black, and girls of other or multiple races or ethnicities had menarche earlier on average compared to non-Hispanic White adolescents.

Dr. Melanie Bone, a consultant OBGYN and U.S. Medical Director at a gynecological health company and virtual women's health clinic Daye, says several potential factors could contribute to the trend of early menarche, including obesity and increased body mass index (BMI) and environmental exposures to endocrine-disrupting chemicals, which can be found in personal care items like cosmetics.

Genetics and ethnicity, psychological stress during childhood, and a diet high in animal proteins, fats, and processed foods may also play a role in early menarche.

Excess body fat, forever chemicals and PFAs, and stress can lead to increased production of hormones like estrogen, potentially triggering earlier puberty.

Bone

The study says that BMI may explain 46% of changes in the time of menarche, suggesting that childhood obesity is a risk factor for earlier puberty.

In the past three decades, obesity has tripled in adolescents, reaching epidemic levels in the United States. Over 20% of teenagers aged 12 to 19 now have obesity, which may impact their psychological, cardiovascular health, and overall health.

Periods are becoming less regular

The menstrual cycle typically becomes regular within the first two years after menarche. Bone says it is common for adolescent patients to experience irregular cycles as their bodies adjust to hormonal changes.

However, the study found that the number of girls reaching regularity within two years decreased from 76.3% to 56.0%, and the number not yet in regular cycles rose from 3.4% to 18.9%.

Bones says persistent irregularities or the absence of periods for more than three months after the first year of menarche should be evaluated by a healthcare professional, as they can sometimes signify underlying conditions like polycystic ovary syndrome, thyroid disorders, or other hormonal imbalances.

She says, "Every individual's cycle is unique, and what is considered 'normal' can vary - less than 30% of patients actually have a 28-day cycle, despite this being often quoted as 'normal.'"