The system has changed. You get an interview appointment on the website. Even better you get to select the appointment date aswell now. You carry your passport with you. If they keep the passport you get a visa and even then they might reject you later. Else hand it over to you on the spot saying you can apply again as soon as the next day.
The US intelligence does a background check on the individual applying for the visa, even if I say they have a spy on your back that wouldn't be wrong too.
That is one reason you don't need any documents to take along on your interview to apply for the US visa.
For the thread poster.
Be as honest as possible, no need to hide any thing. Keep it clear you are visiting family for the baby delivery. No need to mention ghuma phirakei.
You will need to add family because you will staying with them. And your cost of living in the US would be less.
You can add travel/tourism aswell. Also mention what ever source of income you have and how are you going to pay for the trip if you have no legal income in your name.
You would need your family business work letter, leave letter and a letter stating that they are willing to sponsor your trip.
Rest assured, their is no particular ratio of you getting or not getting the visa.
Before you arrive for the interview, it is already decided if you are getting a visa or not.