Research shows that the age at which girls get their first period has decreased over the past fifty years.
Harvard researchers found that girls who are now between 19 and 24 years old had their first period on average at age 11, compared to women now between 55 and 74 years old who were on average 12 years old when they got their period for the first time.
In fifty years’ time there will also be an increase in the number of girls under the age of nine who start menstruating.
The trend could be due to rising childhood obesity, the researchers said. Previous research has linked the phenomenon to the consumption of junk food, chemical pollution and certain pollutants.
Menarche, the first time girls get their period, usually occurs between the ages of 11 and 15, according to the Cleveland Clinic.
Harvard researchers found that girls who are now between 19 and 24 years old will be an average of 11.9 years old before their first period, compared to women now between 55 and 74 years old who will be an average of 12.5 years old were when they first got their period.
The researchers studied 71,341 people as part of the Apple Women’s Health Study, which used cycle data from iPhones and Apple Watches in addition to surveys to gain additional information about the menstrual cycle.
They also found that Asian and non-Hispanic black participants were more likely to report an earlier period.
Other studies have suggested that this is unlikely to be due to genetic variations, and may be caused by “other environmental or contextual factors that, through racism, may influence different pathways, leading to earlier menarche,” the researchers said.
Menarche, the medical name for girls’ first periods, traditionally occurs between the ages of 11 and 15, according to the Cleveland Clinic.
Girls in the study also reported that it took longer for their menstrual cycles to become regular.
The number of participants whose cycles became regular within two years of the start of menstruation has decreased over the past fifty years.
The percentage of participants who had their period under the age of 11 has increased over the years
The number of participants who reported regularity within two years of the start of their period has declined over the past fifty years
Zifan Wang, the lead author of the study, said The Washington Post It was concerning that girls seemed to take longer to achieve a normal menstrual cycle.
‘This is also very concerning because irregular cycles are a key indicator of adverse health events later in life. It worries us.
“We need to do more early counseling and interventions for irregular cycles in children and adolescents,” said Dr. Wang.
Irregular periods have been linked to several diseases, including coronary heart disease, type 2 diabetes and rheumatoid arthritis.
The data also showed that the proportion of girls with very early periods (before the age of nine) was higher in the latest birth group compared to the earliest group.
The decrease in age at first menstruation could be due to increasing childhood obesity, the researchers said, as it is a risk factor for earlier puberty.
Overweight children have higher levels of sex hormones and leptin, a hormone produced by fat cells that can accelerate puberty.
Although childhood obesity may play a role, the decline in age at first menstruation began before the obesity epidemic, suggesting that other factors may be at play.
A big problem is forever chemicals – a group of about 15,000 man-made chemicals found in everything from consumer products to food and water.
These can disrupt hormones, possibly causing puberty to start earlier.
Things like poor diet, including lots of sugary foods, stress and adverse childhood experiences can also influence the onset of puberty.
Other research has shown that very early puberty increased during the pandemic, which may have been due to the stress it caused in the lives of young children.
The research was published in the journal JAMA Network.