The No Surprises Act (45 CFR 149.610) created the Good Faith Estimate as a federal right for all patients scheduled for non-emergency care. A C-section, whether planned in advance or scheduled during a prior hospital visit, qualifies. Each provider involved in your care owes you a separate estimate, and they must deliver it at least 3 business days before your procedure.
For a C-section, that typically means four separate estimates: the hospital (facility fee, OR time, recovery room, nursing care), your OB or maternal-fetal medicine specialist (surgeon fee), the anesthesia group (epidural or spinal block), and sometimes a surgical assistant billed by a separate group. Don't assume the hospital GFE includes all of these. It usually doesn't.
You also have the right to a consolidated estimate if your providers are part of the same health system. Ask specifically if that's available, because it's easier to review one document than four separate billing statements.