You can apply for the new H4 abroad instead of the extension.
The above is intended only as general information, and does not constitute legal advice. You must speak with an attorney to discuss your individual case.
Your wife can depart the U.S. while her I-539 is still pending and return with a consulate issued H-4 visa stamp.
However, should USCIS learn of her departure prior to the I-539's adjudication, her application wil
be deemed "abandoned" and she will also be deemed having been "out of status" from the moment her old I-94 card expired.
Behar Intl. Counsel 619.234.5962 Kindly be advised that the answer above is only general in nature cannot be construed as legal advice, given that not enough facts are known. It is your responsibility to retain a lawyer to analyze the facts specific to your particular situation in order to give you specific advice. Specific answers will require cognizance of all pertinent facts about your case. Any answers offered on Avvo are of a general nature only, and are not meant to create an attorney-client relationship.