Will I lose my US visa if I'm going to have my delivery in the US without having enough money to pay the bills?

If a person has a baby in the USA, while on a tourist visa, the fact that they can't pay the doctor or hospital bill is not a reason under the law for revocation of a visa. On the other hand, a border officer or consular officer has wast discretion if you happen to come in contact with them.

Well, if you do not find a way to pay back the hospital bills, chances are, you will not get another visa to enter the US again if you leave. I have had this happen to another person: She was stopped at the US border an denied entry because she did not pay her hospital bills when she had her baby here.