If you don’t do before....any test isn’t valid.
From scientific perspective
But if you had kids fine before and have a problem after it would be anectodal and something to consider.
Its just like with any before and after.
I might have scarring on my lungs from ....sheesh..I cant remember what it is called at the moment but it was seen on my spleen in a CT...but I dont know because my lungs have never been scanned.
So now later when they are scanned from some disease we dont know what attributed to what on that scan.