If a girl is pregnant and does not want her parents to know, but she is still on their medical insurance, how does that work? Would they find out when they get billed for her treatment?
l know it is logical to assume I am the girl in question but I am really not. Thank you for your concern, though! :)

Yep.

Yes. She better get ready to sit down and have a talk with them.

yes they would find out from the bill sorry just tell your parents its not the end of the world.

Yes. Since u r not on an individual policy, the confidentiality clause doesnt apply to you. The policy owner (your parents) will obviously know what their insurance is used for, since it goes towards their annual deductible & they get billed for their portion.
There r specific details on the bill for what treatment was done at what location, so definitely.
Why doesnt the ''girl'' just tell her parents, so that she can get the support she needs during the pregnancy. Its tough to do this alone, & Im sure her parents wont disown her.

It depends on the type of insurance the parents have. Prenatal care and regular prenatal testing would NOT show up on the typical EOB statement. Hospitalization would.