Period poverty: Why are girls so embarrassed about their period?
Periods are a normal part of growing up for girls.
But did you know more than 60% of them are skipping school because they're embarrassed or anxious about their time of the month.
That's according to one of the UK's biggest children's charities Plan UK International.
It was recently announced that period products would be free for children in schools in England, Wales and Scotland but Northern Ireland has yet to follow.
We've been to speak to some kids in Cambridge who say people just need to be more open about it.
Watch: Operation Ouch looks at what happens to our bodies as we grow up.