New evidence suggests early puberty can be triggered by pandemic stress

The patient presented with underarm hair, breast development and rapid growth — nothing out of the ordinary for a young adolescent going through puberty. The only thing is, she was just six years old.

New research published Thursday in the Journal of the Endocrine Society indicates cases like these, officially called early or precocious puberty, have been far more common among girls in the pandemic than in years prior. Between March 2020 and June 2021 — when Italy closed schools, parks, and gyms in response to the virus —  the number of girls presenting to one Italian center with early puberty nearly doubled compared to years prior.

"The findings are not surprising based on the anecdotal experience of people in my specialty," Dr. Louise Greenspan, a pediatric endocrinologist with Kaiser Permanente, San Francisco, told Salon in a phone interview. "It's consistent with what we've been seeing."

Early puberty, generally defined as sexual maturation before age eight in girls and nine in boys, is uncommon, affecting as little as one in 10,000 children pre-pandemic. It is 10 times more common in girls than in boys, although the reasons behind this sex difference are still somewhat mysterious.

Parents who suspect their child is going through early puberty should bring it to the attention of their pediatrician, Greenspan said. They will help decide on whether to pursue treatment, including puberty blockers, to pause development. Early puberty has been linked to other health problems down the line such as heart disease, cancers and mental health problems, including eating and anxiety disorders. 

Precocious puberty was rising before the pandemic, by about three months per decade since 1977. But the pandemic seems to have accelerated this increase. The spike in cases observed in 2020 has been reflected in several studies measuring early puberty in girls around the world: Another study in Italy, as well as data from Turkey and a U.S. center, all suggest between two and three times as many girls came in with early puberty compared to pre-pandemic years.

Although it's unclear what is triggering this phenomenon, researchers suspect the consequences of lockdowns, like stress and children spending more sedentary time on screens, are likely to blame. In general, chronic stress ages the body — and prior data has specifically shown stressors like the absence of a father figure have been associated with early puberty for some girls.

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"We know chronic psychosocial stress can lower the age of puberty onset," Greenspan said. "So was that part of the problem?"

Body mass index is one measure that has also been correlated with early puberty in girls. In the study published Thursday, girls who started puberty early did have higher BMIs than girls who did not, said study author Dr. Mohamad Maghnie, of the University of Genoa and the Giannina Gaslini Institute in Italy. 

Girls in Maghnie's study were relatively sedentary during this time period, which may have had an effect. "These girls spent an average of two hours per day using electronic devices, and 88.5% of them stopped any physical activity," Maghnie wrote to Salon in an email.

Other data has indicated that changes in sleep cycles or exposure to endocrine-disrupting chemicals could also be influencing the age at which girls enter puberty.

In the end, early puberty is just one piece of the puzzle helping to explain why women's reproductive years are getting longer, with some evidence suggesting menopause is also occurring later. 

Greenspan says the spike in early puberty in the pandemic is likely due to social rather than evolutionary changes because the latter would take far longer to play out. Regardless, it's clear that something in the social or physical environment is reshaping the development of today's girls — and it seems to have been exacerbated by the pandemic.