There's probably a point where it's unhelpful because you're panicking and need to concentrate but it's not the screaming that's bad it's the panic.
A while before I got PG with DD my appendix burst, I passed out from the pain, and nearly died from hospital negligence - so having a pain in more or less the same place just as bad, but not able to pass out every three minutes was fucking terrifying.
I need the drugs to calm down and get back in control and then I did some grunty shouting at the end from exertion.
But sure you can judge me. It's only you that'll look like a twat if you do...