I'm a green card holder, my mom applied for the US visa but with no luck, she was told she's applying for the wrong visa type.

She should be applying for a B-1/B-2 visitor visa. The problem is that with two children who are lawful permanent residents the consulate may rightfully believe that she intends to immigrate to the US and is not truly a nonimmigrant. If she is still legally married to your father, that may be another ground for rejection since spouses of US citizens are presumed to be intending immigrants. You should consult with a competent immigration attorney for advice specific to to your situation. Unfortunately, no one can guarantee that she will get a visa to be with you during your delivery. Good luck to you and congratulations on your pregnancy.

It sounds as if her visa was denied because of a perceived immigrant intent. As a US citizen you can petition for her, but that will take time. You should consult an immigration attorney in your area directly to explore other options, perhaps on humanitarian grounds. But ordinarily merely being pregnant is not sufficient for this as that is the case for many, many people who want their relatives around. It may be easier if you need your mom for you to travel to see her (if your pregnancy allows).

B-2 is the applicable visa. It's a temporary intent visa and an applicant is often asked to demonstrate strong ties to home country or to establish that he/she will return. In your particular situation, its difficult, but not impossible. Consult an immigration attorney - on how to put up the paperwork. Good luck.

You did not state which type of visa your mother tried to get so I cannot tell you if it is the correct one. Generally for your situation, your Mother should probably apply for a B2 visitor's visa. She would to show the reason for her trip and ties to her home country such as employment, property and other family.

It sounds like your mom applied for a visitor visa? An attorney knows what the officer is looking for, and may be able to help your mom be successful by showing her ties to her home country in a stronger application than she had submitted. However, it may be possible for you to petition for your mom to get her green card. Unfortunately, she probably won't be here in time for your delivery, but could over a few months get her green card and be in your life more permanently. As a legal permanent resident you can apply for her, but it will take a lot longer than if you were a citizen. So, if you can naturalize, you can shorten the wait time. To naturalize, you need to have been a green card holder for 5 years (three if you got your card through marriage). Then file your petition. As soon as you are sworn in, you can petition for your mom. Otherwise, I would recommend that you or your mom obtain an attorney to help with the visitor visa application. Our, even better, do both. Best of luck!