after applying EB1_back china

my hu*****and is going to apply EB1 outstanding research and I am F1 now. Now I want to go back China for 2-3 months [before it is approved]. I was told that it is very risky and I had to wait till my I140 is approved. Is there anybody who could give me more information about this issue.

Since I really know nothing about it, any hint will be appreciated.

Thanks.