Hi, welcome. How far along are you? So cortisporin ear drops are pregnancy category C. This means they can't rule out adverse reactions to a fetus but mostly because it wasn't studied in humans. Ani al studies showed an adverse event but remember, thy often use bigger doses than anyone would really take in animal studies. It is prescribed when the need is bigger than the off chance of a side effect with a fetus. Pregnancy Category C basically really means not studied fully.
What was it prescribed for? Can you ask your doctor about it? I was always super conservative during my pregnancies and didn't take anything I didn't have to. See what your doctor says. If you just have it from a previous time you used it, then no, don't use it in my opinion.