Obstetric billing is built around a global maternity package that bundles routine antepartum care, delivery, and postpartum care into a single code, while gynecologic billing looks more like standard surgical and E/M billing — and mixing the two billing logics up is the most common OB/GYN coding mistake.
Why This Specialty Is Billing-Complex
Because the global OB package is billed once at the end of pregnancy (or split into components if care is transferred), individual antepartum visits are not separately billable once the patient is enrolled in global care, which trips up practices used to billing every visit. Gynecologic surgical codes, by contrast, follow normal global-period and modifier rules similar to other surgical specialties.
Common CPT, ICD-10 & HCPCS Codes
- CPT 59400 — routine obstetric care including antepartum care, vaginal delivery, and postpartum care
- CPT 59510 — routine obstetric care including cesarean delivery and postpartum care
- CPT 59425/59426 — antepartum care only, 4-6 visits / 7 or more visits
- CPT 58150, 58558, 58571 — hysterectomy variants (abdominal, hysteroscopic, laparoscopic)
- ICD-10 Z34.0x — supervision of normal first pregnancy
- ICD-10 O-codes — pregnancy, childbirth, and puerperium complications, coded by trimester
Documentation Standards
The record needs to clearly show when a patient entered global OB care and whether all antepartum, delivery, and postpartum care was provided by the same practice; if care was transferred mid-pregnancy, the note should support billing antepartum-only or delivery-only codes instead of the global package. Trimester-specific ICD-10 codes must match the actual gestational timing documented in the chart, not just the diagnosis category.
Common Denial Reasons & How to Prevent Them
- Denials for billing individual antepartum E/M visits separately when the patient is already in global OB care
- Denials when the global package is billed but delivery or postpartum care was actually provided by a different practice
- Missing trimester specificity on pregnancy-related ICD-10 codes
- Bundling denials on gynecologic surgical add-on procedures without the correct modifier
Tools That Help
ICD-10-CM Search · Denial Code Lookup · Modifier/POS Reference · RCM Calculators · NPI Lookup