To Immigrate or who knows

For NIW. Your answer as follow:

Failing of getting I140 and I485 approval won't affect your current non-immigrant status. That's why keeping valid non-immigrant visa status is so important before your approval of I140. Good luck

My case:
If my hu*****and file I140 and I485 for both of us, without knowing the result of I140, once I140 is denied, I heard that being a F1 visa holder I can not continue to stay in F1, and have to change my status to H4.

Question:
Which one is ture?

Sorry for bothering, it's not the case I don't believe you, just facing this important issue, I have to make sure for my future.
Thanks,