Should students (school, college, university) be allowed to go to the toilet in the middle of class?

I thought it would be interesting to see the answers.

I think it's cruel when teachers don't allow people to go to the toilet when they need to.

They might be on their period, and yes they could go at break time, but some people have extremely heavy periods and need to change their sanitary products frequently.

There was a time I had a UTI and wasn't allowed to go to the toilet, which ended up in it getting worse (I don't them and they thought I just wanted an excuse to get out of lesson).

Some people just simply need to go and for some reason are not allowed to.

Teachers tell you things like 'you should get yourself into a pattern' but can we really control when we need to go?

What do you think? Are there any teachers here that want to give their input? Have you had any bad experiences when you was kept from going to the toilet?