Periods are starting younger and we're struggling to pin down why

Menstruation is occurring earlier and earlier in life for younger generations in the Western world, but researchers are puzzled as to why

The age at which menstruation begins has been declining in Western countries for decades – and a new study indicates that in the US, the trend isn’t slowing. What’s more, multiple factors are probably contributing to the problem, making it almost impossible to combat.

This is worrying, given that menstruating before age 12 is linked to an increased risk of conditions like heart disease and certain cancers, says Lauren Houghton at Columbia University in New York, who wasn’t involved in the new work. For…