Could the Pandemic Be Accelerating Puberty?

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When I became a mother ten years ago, I realized I needed to be honest with myself the puberty years. I was not going to be a parent who laughs lightly when her daughter rolls her eyes at her or slams the door. I wasn’t going to embrace the emotional push-and-pull of the preteen years. I could try to empathize by recalling my own trespasses—the argumentativeness, the rebelliousness, the egocentrism. But I was eleven or twelve when I underwent these physical and emotional upheavals, and the data show that in recent decades, kids—especially girls—are starting puberty much earlier than in the past. (Girls tend to go through puberty between ages nine and 13, but the average age has been creeping toward the younger end of the spectrum). It’s distressing enough for an eleven-year-old to bud and sprout; for her skin to break out in zits or grow hair in places, and her mind to temporarily lose its grounding. Imagine how it feels when it happens to a seven- or eight-year-old.

Is puberty happening even sooner — or at a faster tempo — during the pandemic? Would the nine-year-old who has developed a chest since last March have had a camisole-free year otherwise? I have my own suspicions about the impact of the pandemic — lockdowns, stay-at-home orders, virtual schooling — on child development, suspicions bolstered by talk at the park or the playground. Moms are speaking in socially-distanced stage whispers about their children, especially their daughters. It’s happening, now, yes, already. As if the circumstances of the pandemic have triggered a shadow pandemic, one of rampant puberty. Of course, it’s possible that parents just notice their kids’ growth spurts and emotional fluctuations more in the last year because everyone’s at home all the time. Or, is there something more to it?

The big idea: The COVID-19 pandemic may be accelerating puberty in kids—especially girls—causing them to mature faster physically.

Why this matters: Early puberty raises multiple risks for girls. It throws physical and social-emotional development out of sync, which increases the risk of depression, anxiety, and high-risk behaviors (smoking, drugs, unprotected sex) and poor school performance during adolescence, with enduring mental health problems into adulthood. Girls who start menstruating earlier than age 12 are at increased risk of breast cancer later in life due to a longer lifetime exposure to estrogen.

Puberty also triggers an overhaul of brain development, possibly curtailing some of the cognitive flexibility of childhood. (As the philosopher Antonio Gramsci gravely observed: “After puberty, the personality develops impetuously and all extraneous intervention becomes odious.”) Let’s avoid the rush, right?

The possible evidence (so far): Stay-at-home orders and school closures during the pandemic exacerbate some of the major risk factors that may trigger puberty: weight gain, sedentariness/lack of exercise, Vitamin D deficiency, and mental health problems. Let’s take a look at each:

• Weight gain: School closures are predicted to worsen the child obesity crisis. Increased snacking, especially on junk food, and increased inactivity may lead to weight gain. Studies have found that girls (but not boys) with early puberty are significantly likelier to be obese than normal weight. Excess weight gain leads to insulin resistance, which indirectly increases girls’ estrogen levels and triggers breast development. Menstruation usually begins around the time a girl reaches 100 pounds.
• Melatonin deficiency: The hormone melatonin may inhibit puberty, and melatonin may be suppressed during the pandemic. Melatonin normally rises at night, before bedtime, as it gets dark. When kids are no longer on regular school schedules, they may stay up later, often in front of a blue-light-emitting TV or computer screen, which suppresses melatonin. One study found that boys and girls aged 9 to 15 who were in the earlier stages of puberty were especially sensitive to light at night compared to older teens. Another found that the less active a girl is, the lower her melatonin levels, strengthening the idea that the sedentary lifestyle under stay-at-home orders may suppress this hormone so much that the normal brakes on puberty wouldn't work as they would otherwise.
• Vitamin D deficiency: Children who are remotely schooled during the pandemic may be likelier to be deficient in Vitamin D for the same reason that affects melatonin: less exposure to sunlight during the day. A recent meta-analysis has shown that girls deficient in Vitamin D are likelier to develop precocious puberty.
• Mental health: Anxiety, stress, and family dysfunction erode kids’ emotional stability. Previous studies have found consistent associations that tie early puberty to household dysfunction and child maltreatment. Psychosocial stress is a cue for environmental risk and triggers early maturity. The theory from an evolutionary perspective is that girl would have a greater chance of surviving and passing along her genes if she were to mature faster and strike out on her own.

In early support of the pandemic-puberty hypothesis, a small retrospective study of Italian girls found an increase in cases of precocious puberty and an acceleration in the rate of pubertal progression over four months (during and right after a COVID-19 lockdown) compared to previous years.

Test This!

There’s little data yet on how the pandemic-related closure of schools and disruptions to routines and social relationships affects puberty. We need more retrospective studies, worldwide, to compare rates of early or accelerated puberty for both girls and boys during the pandemic than in previous years. We also need post-pandemic longitudinal studies, tracking the population of 7- to 12-year-old girls through adolescence into adulthood, with the full spectrum of racial representation, to determine if and how a year or more of stay-at-home orders and/or virtual school affects their development.

If evidence does find that puberty hastened during the pandemic, researchers will also need to explore if it slowed down afterward or continued at the same pace. Here’s an appeal, too, for further investigations on the effects of deficiencies in D and melatonin, along with weight gain and stress, on the timing and tempo of puberty. Families may benefit from increased public health messaging about the importance of Vitamin D, sleep, exercise, and screen-time limitations and their possible effects on timing of puberty, both during and after the pandemic.

The author's books include Do Chocolate Lovers Have Sweeter Babies?: Exploring the Surprising Science of Pregnancy and Do Gentlemen Really Prefer Blondes? on the science of love and attraction.