I94 expiry abd 240 days about to reach … what does us laws has for pregnant women 
of 6 months to stay at USA .
What Visa status are you ? In general, there is no specific law for pregnant women.
Currently she is in L2 visa dependent on l1 visa . But her i94 valid 2021 and visa stamp on jan2022.
but currently primary applicant l1 applied extension and reaching 240 days by Jan 15th.
Not sure how to hold pregnant l2 holder in USA as painful to travel
It is fine to stay on L2 and wait. Hopefully, your result is positive. Worst case scenario, you can apply for B2 for both asking for it as your situation is extreme and they will consider it as medical. Nothing to worry.