Start your period before age 10 — or after 15? How it can impact your lifelong health, from obesity to heart issues

Your period could be crampin’ your style — and your future health.

Girls are reaching puberty faster than previous generations, a phenomenon perplexing researchers.

The average age of the start of menstruation decreased slightly from around 12.5 years in the 1950s and 1960s to 11.9 years for those born between 2000 and 2005.

Research indicates that approximately 2% of girls begin menstruating after 15 — even fewer experience it before the age of 9.

That’s good news, as a new study out of Brazil links early or late menstruation onset to health struggles later in life.

“We now have evidence from a large Brazilian population that confirms how both early and late puberty can have different long-term health impacts,” said study author Flávia Rezende Tinano of the University of Sao Paulo.

“Most women can remember when they had their first period, but they might not realize that it could signal future health risks.”

Tinano’s team analyzed data from over 7,600 women 35 to 74 years old.

The women were divided into three categories based on the timing of their first period — “early” (less than 10 years old), “typical” (10 to 15) or “late” (older than 15).

The participants’ health was assessed through interviews, physical measurements, lab tests and ultrasound imaging.

The researchers determined that women who began menstruating before age 10 were more likely to develop obesity, high blood pressure, diabetes, heart problems and reproductive problems like preeclampsia over time.

Women who got their first period after 15 were less likely to be obese but more likely to have irregular periods and certain heart conditions.

“Understanding these links can help women and their doctors be more proactive about preventing conditions like diabetes, high blood pressure and heart disease,” Tinano said.

The study was presented this week at the Endocrine Society’s annual meeting in San Francisco.

Menstruation is the monthly shedding of uterine lining, signaling that the woman is not pregnant.

Past research has suggested a link between late menarche and an increased risk of osteoporosis, fractures and Alzheimer’s disease.

Starting menstruation later means delayed exposure to estrogen, a key hormone that protects and builds bone density.

On the other hand, starting menstruation earlier means higher lifetime exposure to estrogen, which stimulates breast tissue growth and development and may create a hormonal imbalance.

Early menarche has been associated with elevated risks of heart problems, Type 2 diabetes, breast cancer, anxiety and depression.

Researchers haven’t pinpointed exactly why girls are going through puberty earlier than before.

Some have pointed to increased rates of childhood obesity, greater exposure to endocrine-disrupting chemicals and higher stress levels.