Category: Physiology

Megan Gray was eight years old when she got her first period. She was playing hide-and-seek with her older sister and a friend at their friend’s house in suburban Sacramento. She was wearing pink jeans, which she had saved up for a long time to buy. She tied a sweatshirt around her waist to hide the bloodstain, and, later, threw the ruined pink jeans away; when her mother asked where they’d gone, she threw a tantrum to deflect the question.

Gray had a close relationship with her mom, but she was so young that they’d had no conversations about puberty; her older sister had not yet gotten her period. “There was nothing, no context for understanding,” Gray told me. “I knew what a period was—I didn’t think I was dying or anything. But still, I didn’t tell anyone for months. I just used wadded-up toilet paper. It felt so awkward and shameful.” She did eventually talk with her mom about it. But this was the nineteen-eighties.

“It wasn’t some big informational session. It was very Gen X—you just dealt with things by yourself and got on with it.” Gray was taller than her peers and wore layers of tops to conceal her developing breasts. She estimates that she was a C-cup by fifth grade. “There were assumptions about me because I had boobs. And I had never even kissed anyone. I was lucky, because nothing traumatic occurred. Yet I do think that there is a trauma in being sexualized.”

Maritza Gualy got her first period when she was eight going on nine, at the end of the eighties. Her mom showed her how to use a thick Kotex pad. Eventually, her older sister introduced her to o.b. tampons—the ones with no applicator; they were small and easier to hide. The sisters, whose parents were Colombian immigrants, attended a majority-white Catholic school in Nashville.

Her school uniform had no pockets, so whenever Gualy had her period, she had to hide tampons in her bra or in the waistband of her skirt. One day, an o.b. fell out of her skirt when she and her classmates were sitting on the rug together. Later, when they were back at their desks for a spelling test, Gualy recalled, “the teacher went around from kid to kid with the tampon. ‘Is this yours?’ ‘Is this yours?’ Except she was only asking the more well-developed girls! I knew I wasn’t going to admit to it.”

In fifth grade, Gualy’s best friend got her period, and she was upset to learn that Gualy had started hers more than a year earlier and hadn’t mentioned anything. “But I already felt so othered,” Gualy said, “and I didn’t want to add to that.” When Gray and Gualy were kids, pediatricians thought that the average age of onset of puberty in girls—defined in most medical literature as thelarche, when breast tissue begins to develop—was about eleven years old. Menarche, or first period, was thought to happen around age thirteen.

Only a small percentage of girls had started puberty by the age of eight, much less started menstruating.  But, by the two-thousands, new research had found that eighteen per cent of white girls, thirty-one per cent of Hispanic girls, and forty-three per cent of Black girls had entered thelarche by age eight, according to a study published in 2010.

Often, these girls were taller than most of their peers and showed other signs of accelerated physical maturation, such as pubic hair and underarm odor. Thelarche typically presages the onset of menstruation by two to three years, meaning that some of these girls would have to deal with the mess and discomfort of a monthly period before they’d finished elementary school.

Researchers and physicians hypothesized about possible causes for the increase in early puberty, such as increasing rates of obesity; greater exposure to endocrine-disrupting chemicals found in food, plastics, and personal-care products; and stressful or abusive home environments. Then, during the coronavirus pandemic, pediatric endocrinologists saw a new surge of referrals for girls with early puberty.

Recent retrospective studies from Germany and Turkey show that the number of these referrals doubled or even tripled during the lockdown periods of 2020 (this at a time when many families may have been avoiding non-emergency doctor’s visits for fear of COVID-19). A paper published in August in the journal Frontiers in Pediatrics, which analyzed data from South Korea’s national statistics portal, found that the number of children diagnosed with precocious puberty almost doubled between 2016 and 2021, with a sharp post-2020 spike.

The rise in early puberty “is a phenomenon that is occurring all over the world,” Frank M. Biro, the former director of the adolescent-medicine division at Cincinnati Children’s Hospital Medical Center, told me. (Although there has also been a rise among boys, girls experiencing early puberty still vastly outnumber them.)

The new data may offer some safety in numbers to early-developing girls—if Gray and Gualy were growing up today, they might have found a friend or two on the same accelerated track. But early puberty is associated with a daunting list of adverse physical and psychological outcomes: various studies have suggested that early-maturing girls are at greater risk for developing obesity, breast cancer, eating disorders, depression, and a range of behavioral issues.

Especially in the midst of what is increasingly understood to be a post-COVID youth mental-health crisis, the startling new uptick in early puberty is troubling to some physicians and parents. But, because the spike appears to have been triggered within a compressed, well-defined timeframe, it also offers rich terrain for better understanding the condition’s causes and effects.

It also provides a chance to rethink puberty: to see it not as a gateway into adulthood but as another stage of childhood—one that is highly variable from kid to kid and need not be cause for alarm. “We are in a great natural experiment at the moment, and we might not know the results of it for another ten years or more,” Louise Greenspan, a pediatric endocrinologist at Kaiser Permanente, San Francisco, said.

“I do wonder if this is going to be a cohort of kids whose puberty was more rapid because they were in a critical window of susceptibility during a time of great social upheaval.” For generations, pediatricians have referred to a table of pubertal development known as Tanner stages, named for the pediatric endocrinologist James Tanner, one of the lead investigators of the landmark Harpenden Growth Study, conducted from 1949 to 1971 at a charity home for orphaned and neglected children in a suburb of London.

There, hundreds of boys and girls were photographed naked at three-month intervals. Although the data for the Tanner scale were gathered from kids of a narrow demographic—white, thin, and bearing the internal scars of trauma or adversity in their formative years—it established, in a pair of papers published in 1969, our modern benchmarks of puberty: five distinct stages, ranging from prepubertal to fully developed.

On average, the girls in the study began showing breast buds—the “Tanner II” stage—at age eleven or so, and began menstruating between thirteen and fourteen. Early puberty is identified through physical examination, blood tests to measure levels of sex hormones, and a bone X-ray to estimate “bone age”—how close a child’s skeletal system is to reaching maturation.

Puberty typically begins in girls when the pituitary gland starts secreting hormones known as gonadotropins; these hormones cause the ovaries to grow and to produce estrogen, the sex hormone that triggers the development of secondary sex characteristics…Read more