The average age of the start of puberty dropped in the last century, some girls beginning to see their chest develop from the age of six or seven years. According to experts, these changes in the chronology of reproductive development could have serious consequences on the physical and psychological health of the female population.
In a meta-analysis bringing together thirty studies, researchers have found that the average age of the start of puberty among girls around the world fell by decade between 1977 and 2013, which represents more than a year ahead. The first sign of puberty in girls is the development of mammary tissue, the appearance of the first rules (or menal) being later.
A study published in the May 2024 issue of JAMA Network Open suggests that the development of these two physiological markers seems to be done at a younger age. This study revealed that in 71,341 women born in the United States between 1950 and 2005, girls had their first rules at a younger age and that it takes more time for them to become regular. During the fifty-five-year period that the study covered, the number of young girls with first early rules (that is to say before the age of eleven) almost doubled to reach 16 %.
“It is a well documented and global phenomenon,” says Lisa Swartz Topor, an associate professor of pediatrics at the Warren Alpert Medicine School of the University of Brown and at the Hasbro Children’s Hospital in Providence, in Rhode Island. As for the reasons for this phenomenon, at this stage, “there are more questions than answers,” she explains. “This is a confluence of many different things, the main theme being the changes in our world in the last two centuries. »»
At any age, the start of puberty is triggered by the hypothalamus in the brain, which secretes the gonadoliberin hormone (GNRH). The GNRH, which has been described as “key regulator of the reproductive axis”, stimulates the pituitary gland in turn to secrete the luteinizing hormone (LH) and the folliculo-stimulant hormone (FSH), which triggers puberty. In girls, these two hormones indicate the ovaries to start freeing estrogens and progesterone, which leads to the development of pubic breasts and hair, the appearance of rules and modifications of the silhouette.
In addition to the potential long -term health repercussions, in case of early puberty, “your child can start to look like a teenager or behave as such before you expected,” explains Natasha Chaku, psychologist and assistant professor in the Department of Psychological and Brain Sciences at the University of Indiana in Bloomington. As a result, “parents may need to discuss how their bodies will change earlier than they think. »»
According to experts, this is a multifactorial problem. On the one hand, infantile obesity rates have increased since the 1970s and certain studies have established a link between obesity and early puberty in girls.
In particular, “obesity can be associated with the release of different hormones, including insulin, the growth factor similar to insulin 1 and leptin, in blood circulation”, explains Aviva Sopher, aggregated pediatric teacher at the Irving Medical Center of Columbia University in New York. These hormones can affect appetite and satiety as well as the accumulation of body fat and they can have an impact on the gonadotropic axis and therefore on the start of puberty.
The quality of children’s diet can also play a role, especially if it is low in fruits and vegetables, rich in animal proteins and highly processed foods, “which are associated with higher levels of sex steroids like estrogens”, notes Franck Biro, teacher of pediatrics at Cincinnati Children’s ME Hospital Medical Center. Chinese researchers have compared three different diets: a traditional diet, an unhealthy diet and a regime rich in protein. They found that consuming a lot of snacks, desserts, fried foods and soft drinks (the “unhealthy diet”) was associated with early puberty in girls.
These factors are associated with overproduction of sex hormones such as estrogens and testosterone, rather than direct effects on the brain.
In addition, more and more research suggests that endocrine disruptors, such as phthalates, bisphenols and other chemicals present in current consumption products, could contribute to these changes.
“Many disruptive chemicals of the endocrine system, omnipresent in our environment, have effects similar to those of estrogens,” explains Sopher. Therefore, strong exposure to these chemicals can change hormonal balance, and alter the development of the reproductive system.
For example, a study published by BMC Medicine revealed that early puberty in girls could be due in part to exposure to fluorinated compounds, present in many products of everyday life, including antitache, paintings, waxes, frames, electronic devices, food packaging and many more.
It is likely that a combination of these factors lead to early puberty in some girls, according to Biro.
These changes in menstrual development can have long -term physical and emotional repercussions. In the short term, “girls who have early puberty grows faster and stop growing earlier,” said Biro. This can result in a final size smaller than the one they could have had if puberty had taken place at a later age.
In the long term, early puberty is associated with a higher risk of developing breast cancer, as well as a higher risk of obesity in adulthood, notes Franck Biro. It is also associated with an increased risk of high blood pressure, type 2 diabetes, metabolic syndrome, cholesterol abnormalities and cardiovascular diseases, according to experts.
“If a girl starts her puberty early, her brain and body are exposed to higher sex hormones than in other girls,” said Chaku. “Other children must make up for their delay. In addition to the fact that these young girls feel out of step compared to their comrades, early puberty can lead to an increased risk of certain mental health problems.
“Early puberty is a more difficult psychological transition,” says Mendle. “Children who ripen early have the opportunity to develop all the social and emotional resources that help them make the transition. »»
Research has shown that girls who undergo early puberty have high levels of depression, stress and anxiety, they also have a less good image of their body and more difficulty regulating their emotions.
“Puberty raises awareness among the parts of the brain which are requested by social experiences. Some of these effects dissipate, but depression may persist, ”underlines Professor Chaku.
“Puberty is not limited to the biological aspect,” explains Mendle. “There are interpersonal and social transitions that occur because they seem older. The rest of the world is starting to treat them differently and they may experience difficulties in establishing friendships. »»
“People think they are older than they are because of their appearance,” said Biro. “They can be twelve, appear fifteen, but feel and act as a twelve year old child. »»
This change of appearance can bring adults, including teachers and parents, to expect these girls to act more mature than they do. If they are starting to frequent a group of older peers, girls who know early puberty can adopt risky behavior, such as drinking alcohol or having sex, adds Mendle.
A girl suspected of ripening too early must be examined by a attending physician, says Biro. In most cases, its development will simply be monitored and it will be advised on the physical and emotional changes it should expect.
“If it is very early and progress quickly, girls must be examined to ensure that this is a synchronization problem and not a pathological cause such as a brain tumor,” said Topor, stressing that the brain anomaly can cause early puberty. “We can press the break button with medication if it happens very early,” she adds.
In this case, doctors can intervene by giving the young girl a medicine, such as an agonist of the gonadoliberin hormone (GNRH), to slow down early puberty in order to prevent some of the harmful effects, such as a smaller size than the target size of the patient. Research has shown that these drugs can increase the final size in girls who have early puberty.
Whatever the moment when puberty begins, it is important that parents normalize the experience as best they can. Remind the child her age and how to take care of herself, even if her body seems to be twelve or thirteen but that she has eight, she must treat her body like that of an eight -year -old child in terms of food and sleep habits, explains Topor.
“It is very important to treat your child in relation to his age, even if his body seems older,” explains Topor. This can help girls feel comfortable with their own body, protect their self-esteem and take care of themselves, physically and emotionally.
“Many aspects of the transition give the impression of being helpless,” says Mendle. “It is something that happens that children are ready or not. »»
This is one of the reasons why parents say and can make the difference, for better or for worse.
“Many aspects of puberty, in particular menstruation, are considered annoying by society,” explains Mendle. “The less the transition is stigmatized, the better. »»
To this end, she adds, it is useful that parents are open to discussion on puberty and that they share their own experiences.
“If girls can learn from this experience and learn from it,” adds Mendle, “they are doing better and can establish a feeling of continuity between their past, their present and their future. »»
