I think a number of women pass a small amount of urine during orgasm, but for some a larger amount is passed and is considered a problem by them.
In an answer to a somewhat similar question , Merely Me , a writer and community leader for this site, gave this answer, in part:
"Although it seems possible that you may leak some urine during this time. Is there any pressure on your bladder from the position you are in for sexual intercourse? I would maybe empty your bladder before having sexual relations to ease this fear.
And is this something you can talk to your spouse about? It seems you are embarrassed but it is likely that he would understand your fear. It seems a shame to forego feeling satisfied because you are afraid this might happen.
And too...are you leaking urine other times like when you cough or sneeze?
This might be an issue to bring up with your doctor. They have heard it all so there is no shame in talking about such things with a doctor."
I hope this help you a little. Seeing a doctor can determine if there is a physical problem and there may be something they are aware of to help you if you wish.