To adults it’s a rite of passage, a symbolic move away from the age of innocence to I somewhere else. To other girls, it’s a phenomenon that they’re partly anticipating, partly dreading themselves. To boys, it’s too gross even to think about.

To Chlo , it’s all those things. But most of all, her first period is a pain in the belly unlike anything she’s ever known. Her mother’s happy surprise and extra attention doesn’t lessen the gut-wrenching cramps that are wracking the 10-year-old’s very being. She just can’t understand how something that her family considers so positive can make her feel so grim.

She’s not thinking of the symbolism of the event. What’s weighing on her mind is the fact that she’s the first one in her class to start, so there’s no one to ask about the practicalities of dealing with periods at primary chool. Like how she goes about changing a sanitary towel without advertising her new status to the world - where there’s no privacy and no locks on doors. How often does she need to change it? What if it leaks through her clothes or down her legs? What happens if there’s no bin in the loo? If she’s feeling too grotty to do PE, what should she tell her teacher? If she can’t go swimming with her class in four days’ time, what is she supposed to do? Will everyone be able to tell that she’s “on”?

It’ll take a few months for Chlo to get into her stride with this messy, horrid business, which, by degrees, will become less messy, less horrid. In the meantime, there will come a new status among the girls in her class which could swing either way. Depending on her standing within the group and the kind of girls they are, she could either be admired or teased. Whatever, the first experience of menstruation in a class won’t be ignored.

By other girls, that is. When it comes to the curriculum, that’s a different story. Despite anecdotal evidence that more girls than ever before are getting their periods before leaving primary school, menstruation tends to get short shrift in personal, social and health education. The reason? Many primary teachers don’t feel equipped to deal with the subject.

But back to Chlo , whose initiation is well and truly underway. She’s got plenty to be dealing with. As all females know, periods don’t just appear and then disappear again every month. Chlo ‘s likely to experience the hormonal rev-up known as premenstrual tension every three to four weeks or so. To a 10-year-old as much as to a 25 or 35-year-old, that could spell a bout of the miseries. So, if you see her alone in the playground, glowering at the girls who at other times of the month are her closest friends or bursting into tears if someone brushes against her shoulder by accident, it might just be that Auntie Flo is about to visit.