The age at which girls are going through puberty has been going down over the past couple of decades.

A generation or two ago, it was almost unheard of that someone under the age of 12 to get their first period, but these days, many girls are experiencing their first menstruation when they are as young as nine and 10 – some even just eight. In the US, the average age of puberty has dropped from the typical, biologically recognised, age of 12, to 10 for females, with black and Hispanic girls often going through puberty around a year earlier on average. This is worrying experts, who are trying to pinpoint the reason for this shift. Speaking to the Daily Mail, many US health professionals are blaming poor diets for pushing up puberty, but there is also a theory that early puberty is linked to an imbalance of certain hormones. Dr Paula Newton, a pediatric endocrinologist at the University of Maryland, theorised to DailyMail.com that fat cells have hormonal properties which could signal the triggering of puberty at earlier ages. And this, Newton reckons, could also explain why precocious puberty rates have grown during the COVID-19 pandemic. A study published in April in the Italian Journal of Pediatrics found that rates of precocious puberty jumped 2.5 fold during 2020 and 2021 when compared to previous years. "As far as what we're seeing during this pandemic, it's more so the sedentary activity and lack of activity, more unhealthy snacking, more ordering out,' Newton explained. "Covid forced many children to spend more time indoors, and not out playing and getting regular exercise that they would otherwise."

Long-term health risks of early puberty

Health experts have had their suspicions for a while that early puberty could be linked to some serious health issues later in life, and some ground breaking research in 2020 established the that there could be an association between early puberty and breast cancer later in life. Experts cannot exactly pinpoint why there is an association between these cancers and early female development. "We’ve known for a while that having a younger age at first menstrual period (early age at menarche) is associated with increased risk of developing breast cancer,' Dr Dale Sandler, chief epidemiologist at the National Institute of Environmental Health Sciences, told DailyMail.com. "While less well-studied than menarche, the onset of breast development, or thelarche, is an early marker of puberty that usually occurs a couple of years before menarche and may also be related to breast cancer risk." Sandler says that experts have not yet nailed down the cause, though, and the link is still tenuous. "We don’t know for certain what mechanisms link early puberty to cancer later in life. Girls experience hormonal changes during puberty, along with changes to the breast tissue itself, that we think could affect breast cancer risk. The breast is thought to be more vulnerable to carcinogens during periods of rapid development, like during puberty." She adds: "Unfortunately, we still don’t know very much about what factors are associated with early puberty. We need more research on factors that occur early in life that could potentially influence the timing of puberty and cancer risk."