Reports from around the world have shown how a surprisingly high number of early puberty cases among girls were seen during the initial stage of the COVID-19 pandemic. Nobody is totally sure why this may be the case, but there are a few ideas that might be able to explain this unlikely link. 

The average age for girls to start puberty is 11, while for boys the average age is 12. Like most biological processes, there’s a fair amount of variation and it's perfectly normal for puberty to begin at any point after 8 in girls and 9 in boys.  

Early puberty, aka precocious puberty, refers to when a child starts puberty before this age. It’s generally more common in girls but remains relatively rare, affecting 1 percent or less of the US population.

In general, people have been reaching puberty earlier and earlier in recent decades. There are many possible reasons for this trend, ranging from increased average body weight to exposure to endocrine-disrupting chemicals in the environment. 

In an unexpected twist, a notable uptick in precocious puberty cases has also been seen since the COVID-19 pandemic kicked off in early 2020. Furthermore, it also appears that girls were generally experiencing puberty during the pandemic more than before. 

In Turkey, doctors observed that girls were hitting puberty during the pandemic earlier than they did before. The researchers gathered 359 girls, finding that the onset of puberty was significantly earlier in the pandemic group than in the pre-pandemic group. They also concluded that the need for pubertal suppression therapy increased during the pandemic.

Over in Italy, a significant increase in early onset puberty was seen. In one case study reported in the journal Endocrine Connections, 338 people were referred for suspected precocious puberty between March and September 2020, compared to 152 subjects in the same period of 2019. The increase was almost solely seen in girls, with scarcely any difference being observed in boys

The team loosely speculated that the link had something to do with the “complex lifestyle changes related to the lockdown.” 

Firstly, they hint that it might have had something to do with the lockdowns and lack of exercise seen during this time. Paired with this, it’s known that gaining fat can be related to an early onset and fast progression of puberty.

Secondly, they float the theory that the psychological stress of the pandemic may have played a role. This is because anxiety in prepubertal girls has previously been associated with early pubertal onset. 

Lastly, they touch on the idea that the pandemic saw increased use of electronic devices. Not only did many of us grow more attached to our smartphones and Zoom calls, but kids also started spending most of their days fixed to a laptop learning from home.

Just a few days ago, a study suggested that exposure to blue light (like the light emitted from smartphones and electronic devices) was linked to earlier puberty onset in female rats. The researchers posited that it was all to do with the artificial light meddling with hormones. Other researchers are skeptical, stressing that there’s no guarantee the findings can be applied to humans. 

The Italian study also points towards the increased use of electronic devices. Instead of light exposure, however, they believe it might have something to do with the endocrine-disrupting chemicals used in the manufacturing of these products.

“Flame retardants have been widely used in the last decades to reduce the flammability of electronic devices. Their effect as endocrine disruptors interfering with pubertal development has been demonstrated in animal and human studies,” the study notes.

The days of lockdown are now behind us – and, according to the World Health Organization, the end of the COVID-19 pandemic is “in sight.” Hopefully, once the dust has settled and the data is in, the explanation behind this curious correlation might be unearthed.