Nineteen parents and guardians have appeared before magistrates in Norfolk charged with the unauthorised absence of their child from school.
The prosecutions at Great Yarmouth Magistrates' Court on Friday concerned 11 children, aged between seven and 15, and all registered at schools in the local area.
Many of the parents were given six-month conditional discharges.
Two of the parents blamed their daughters' absences on school policies disallowing access to toilets during lessons, preventing them from changing sanitary products.
Tina Leslie, the founder of Freedom 4 Girls - a period poverty charity - said it was unfair to penalise girls for something they could not prevent.
'Stigma'
"This has been an ongoing issue for quite some time now. It’s a basic human right to go to the toilet," she claimed.
"A lot of schools have this policy now.
"You have to have a doctors' note or special dispensation to use the toilet when you’re on your period. But periods are a natural bodily function, you can’t hold it in.
"If you do leak, you’ve got the stigma and the name calling. That’s why these kids aren’t going into school."
Pepe Di’Iasio, general secretary of the Association of School and College Leaders, said there had to be policies in place to encourage regular attendance.
"However, what these cases demonstrate is that this issue is not always simple and that children and families face a range of challenges that can make regular attendance more difficult," he explained.
"There needs to be a wider network of services in place to support families when such difficulties arise and enable children to quickly return to the classroom."
Norfolk County Council prosecuted the parents and guardians, and all the absences were recorded between December 2023 and July.
Stuart Dyer, from the council's education department, told the court: "It is always essential a parent ensures their child's attendance to receive their full-time educational entitlement and maximise their chances and reach their full potential."
He said in all cases, schools had reached out to parents with letters, text messages and arranged meetings; some of which were not attended by parents.
Other interventions offered included free breakfast clubs, access to key workers and catch-up sessions.
None of the parents were threatened with imprisonment, as courts can only impose financial penalties.
One of the schools concerned in the prosecution told the BBC in a statement: "Attendance is essential for supporting student learning and positive outcomes.
"We therefore work closely with students, families and the local authority to ensure that this can be achieved, with all possible support provided."