Urgent: H1b transfer and H4 pe

Hi,

My wife filed H4 under my current H1b. Can I do H1b transfer with her h4 pending or I need to wait untill her H4 is approved? My manin concern is, that is it possibly for her to legally stay in the USA, since her OPT will expire next month. If anybody had the same experience and want to share with me, i will really appreciate that. Any advices will be really appreciated.

Thank you very much.

Best regard