For reasons that remain mysterious, puberty starts at an increasingly early age
A few months before her 8th birthday, Caterina* notices that she is starting to grow pubic hair and that the volume of her breasts is increasing. She is very uncomfortable because at school, after the swim class, she takes a shower naked with her classmates who do not share these features. Worried, her mother takes her to a pediatrician. After a check-up, it turns out that, from a medical point of view, there are no abnormalities. However, given the discomfort experienced by the child, the possibility of slowing down the process of puberty is considered. In the end, the family decides to let Caterina grow naturally without intervening and asks the school’s permission so that after the swim class, she can keep her bathing suit on while taking a shower. Caterina’s situation is becoming more and more frequent. In recent years, Michael Hauschild, Clinical Head of the pediatric endocrinology and diabetology unit at CHUV, has observed a “significant increase” in cases of early puberty and treats between 25 and 40 of them per year in his specialized center.
“We know that when there is excess weight, puberty can be more precocious,” says Michael Hauschild, Clinical Head of the pediatric endocrinology and diabetology Unit at the CHUV.
Precocity is when the first signs of puberty, such as an increase in breast or testicle size, hair growth, menstruation, lengthening of the penis, or high growth, appear before the age of 8 in girls and 9 in boys. “Very precocious” puberty is defined as when these features show up before age 6 and 7, respectively.
A universal phenomenon
In 2020, a meta-analysis of 20 countries from all continents showed that the reduction in the age of the onset of menstruation is a universal phenomenon. There is a decline of almost three months per decade between 1977 and 2013.”The average age of puberty has decreased during these decades, with the first signs appearing around age 10 or 11 instead of the usual 14 or 15. Nevertheless, it remains quite normal. Granted, there are more consultations, but we cannot talk about an epidemic of precocious puberty,” says Hauschild. This phenomenon has always existed, he adds. Historically, there have been people who deviate from the norm without it being considered a pathology.
Puberty is a naturally occurring physical event that prepares the body to be fertile, reminds the pediatrician. “Over the past decades and centuries, it has been closely linked to the environment. It occurs when external conditions are favorable. We know that when there is excess weight, puberty may occur earlier.” The expert also points to the link between the precocity of puberty, a higher body mass index, and nutrition. “It is known that among children who do not eat enough, puberty starts later.”
Prevalence of precocious puberty in girls
Earlier puberty can be observed in both girls and boys. However, the latter are about ten times less affected by idiopathic early puberty (independent of a pathology). Indeed, these cases of precocious puberty are more frequently reported in girls—over 80% of cases. This is partly because, in a highly sexualized world, parents are more attentive to the psychosocial implications that early signs of puberty may imply for a girl.
There are also fewer studies on precocious puberty in boys because they consult less. And when they do, they tend to be more concerned about late puberty. However, if they experience early puberty, there is a greater risk—in 70-80% of cases—of finding a pathology: a tumor lesion to the brain or a disorder of the adrenal or pituitary glands, with signs often evolving rapidly.
Causes still unknown
“At the moment, apart from improving health and food conditions, we have no answers to understand what causes puberty to start earlier,” says Michael Hauschild. Are these hormonal disorders caused by the presence of estrogen in animal production, the use of pesticides, or the presence of endocrine disruptors in cosmetics and food products? “These are plausible theories but difficult to prove in humans. Just as it is impossible to say at this stage whether socio-economic conditions or ethnicity can influence the phenomenon,” he says, indicating that another hypothesis is that the disruption of our biological rhythms, related to screen light, could alter hormonal secretion.
The key, says the doctor, is to identify early puberty that is linked to a disorder or disease. “Idiopathic precocious puberty, meaning it is independent of a pathology, can be a variant of the norm without problems; it just occurs earlier than the standard age. The other form may be a consequence of a tumor lesion or a genetic or enzymatic disorder and will necessarily require support.”
Sometimes, identifying the pathology is not easy and requires investigation. “If a 4-year-old develops pubic hair and breasts, everyone will agree that something is wrong. But for a 7 or 8-year-old, it’s not clear. There is a grey area.” To determine if precocious puberty is pathological, hormone levels can be monitored, and the child’s bone maturation can be checked to see if their biological age and chronological age are consistent.
How precocious puberty is treated
Stopping the production of sex hormones
Hormone therapy to curb precocious puberty uses a synthetic product that delays the secretion of puberty hormones; it is injected into the muscle every three months.
Assessing the suitability of a treatment
After getting a check-up, if everything is normal, a treatment to slow puberty may be considered. “Even if, without treatment, this precocity will probably not have an influence on the adult size of the child, nor any other negative physical consequences.” It can still disrupt their psychological development, possibly creating a psychosomatic dissociation. A phenomenon that appears when we measure a gap between the development of the body and the level of emotional maturity says Michael Hauschild. If the child is under 6 or 7 years old, very precocious puberty may lead to a smaller adult since growth stops a few years after puberty.
An average duration of two years
In Switzerland, the treatment costs around 430 francs every three months and lasts two years on average. It is most often prescribed up to the age of 10-11, the average age of puberty, when it will naturally start again.
The doctor states that there are atypical cases of precocious puberty, so-called heterosexual, where girls show virilizing signs (strong acne or a lot of hair) and boys show feminization signs (breast development). This may also be the case for people with rare differences in sexual development, whose genitalia do not correspond to traditional definitions of male or female. When the characteristic signs of one’s sex develop, early puberty is iso-sexual. “These situations can be a warning sign for the pediatrician.” Of course, you have to make sure that you have determined the cause of precocious puberty before proposing a treatment, says the expert. “In addition to medical investigation, the pediatrician, parents, teachers, and family are asked to assess the suffering associated with precocious or very precocious puberty affecting the child; a lot of emphasis is given to the child’s experience.”
* Pseudonym
«JAMA Pedriatrics», april 2020.
Few side effects
The therapy does not influence the child’s growth and final height unless it is started before the age of 6-7. It has few side effects and can be taken safely with other medications.
