Second trimester/B2 visa Port of entry for LPR spouse

[gregspirited]

I'm an LPR working here in US. My wife has a B2 visa and she is pregnant (end of second trimester)  and is out of the country right now. She has been in US before on H4, J1 (medical residency) and B2 (multiple times). She went to her home country in March and I'm planning to bring her back in June (after 3 months out of the country on B2 visa).  I have applied for I-130 for her GC which is pending still.

What are the challenges for her at Port of entry given all the above information? What should I look out for and prepare? Any help is appreciated.