If I had an vaginal ultra sound when I was pregnant because of bleeding, that ended in miscarriage. Would they have been able to tell if I had pcos?

Diagnosis PCOS. Maybe, maybe not. Many cases of pcos do not have abnormalities in the ovaries even though the illness is named polycystic ovarian syndrome. I know it is confusing, but when the syndrome was named they thought that the ovaries always were filled with cysts.
Ultrasound. If you were pregnant at the time, they may be able to see that you had may follicles in your ovaries but not that you had pcos. That relates more to your menstrual history and other symptoms that may occur.