If you have teenagers in your life, you may have noticed that kids these days seem to be getting their periods earlier than previous generations did. It’s not just in your head: A recent study from Harvard’s T.H. Chan School of Public Health confirms what many people have assumed, as well as additional findings about period regularity in younger generations.

The study, which analyzed self-reported data from more than 71,000 participants in the US, found that menstrual periods are arriving earlier for younger generations, with the average age dropping from 12.5 years old for people born in 1950 to 11.9 years old for those born in 2005. More staggering, however, is that both early menarche—a person’s first menstrual period—and irregular periods were much more common in the non-white and low-income study participants. And period irregularity has become more common for younger generations compared to their older counterparts.

These findings are a big deal, because early menarche and irregular periods can be a signal of future health issues, including pregnancy complications and mental health changes. Joining guest host Anna Rothschild to discuss the findings and their implications is lead study author Dr. Zifan Wang, postdoctoral research fellow at Harvard University in Cambridge, Massachusetts.