Is it known why Catherine Howard did not conceive a child while married to Henry VIII?

by Dalekette

Wondering if historians know why she didn't conceive a child. I read that Henry may not have been able to at that point in his life due to the ulcer he had but not sure if that was true or not - not a reliable source. Is it also known if she truly did have an affair?

Lives-to-be-loved

I think she was able to get pregnant but always ended in miscarriage. Poor soul