She could now, just by saying she does (if she’s not trying to defraud anyone), or by court order.
I was quickly named in Chicago in 1959, because the registration of birth required a name, and the default name was “Baby Boy (lastname)”. Although the naming was not compulsory, the registration was.
If my parents had not quickly selected an alternative to BB, they would have had to go through bureaucratic pain of changing my registered name – or leaving it.
Although registration of birth has several civil and cultural benefits, historically it is compulsory to prevent and detect infanticide. Since you will end up in court if you refuse to register, yhe pressure that hospitals put on you to register before you leave benefits the parents as well as the child
In my home town, it used to be the (common law) case that you could call yourself whatever you want. 30 years ago, I can remember a criminal lawyer tripping over his words as he attempted to explain that, although you COULD have as many names as you wanted, it was a bad idea. Unless you registered the name change, the police, courts, tax office and banks would assume that you were using multiple names for criminal purposes.
Since then, my state and federal government have made that explicit: I need to prove my identity using a continuous chain if I want to drive or travel or use a bank.
BTW, in Chicago in the 50’s it was common for poor people to change their name every time they skiped out on the rent & bills. In Cook County Hospital, this meant that you had to interrogate reluctant patients to try to match them up with existing medical records.
…but I can see how a nurse in particular might give you the impression that it’d be illegal. Nurses can be very good at insisting that you do what THEY tell you to do; you have to stand up for yourself and cross-examine them to find out if they’re telling you about actual law, hospital policy, or their own personal, heartfelt opinion. It might be hospital policy, or it might be the nurses’ protocol in making “sure” that you’re showing “proper” concern for baby’s well-being. Nurse-midwives have these sorts of concerns drilled into them as part of their training; maybe obstetrical nurses do, too. What would they do about it if they think you’re not sufficiently concerned about baby’s well-being? The thing to be aware of is that medical clinicians are frequently in that business because they’re type A personalities; they like bossing people around. You might also like to be aware that most women who aren’t physical basket cases can give birth perfectly well at home. You can go get a birth certificate from the town you gave birth in any time afterward.
I don’t believe any state requires you to get one. If a doctor attends the birth, he/she is required to fill one out. Don’t know about midwives–probably depends on the state.
Ohio requires that all births be registered within ten days. It explicitly says that other people in attendance or the parents have to do it if there is no doctor.
ETA: http://www.portal.state.pa.us/portal/server.pt/community/live_birth_registration/14277
http://www.cdph.ca.gov/certlic/birthdeathmar/Documents/Out-of-Hospital%20Birth%20Package.pdf (PDF)