Fetus and Obstetrical (BY) ICD-10-PCS
The BY body system covers Imaging procedures on fetus and obstetrical, with 31 ICD-10-PCS codes across 2 root operations, 29 of them billable in fiscal year 2027. Each root operation defines a distinct procedural objective, and the info icons show the official definition with a preview of the codes inside.
Root Operations in This Body System 2 operations · 31 codes
| Chars 1–3 | Root Operation | Codes | Billable |
|---|---|---|---|
| BY3 | Magnetic Resonance Imaging (MRI)Computer reformatted digital display of multiplanar images developed from the capture of radio frequency signals emitted by nuclei in a body site excited within a magnetic field | 22 | 21 |
| BY4 | UltrasonographyReal time display of images of anatomy or flow information developed from the capture of reflected and attenuated high frequency sound waves | 9 | 8 |
The info icon shows the official root operation definition and previews the codes in that range.
About the BY Body System
These imaging codes cover fetal body parts, the whole fetus, the umbilical cord, and the placenta. The body part value can also identify the pregnancy trimester and whether it involves a single fetus or more than one.
Magnetic resonance imaging (MRI) uses magnetic fields and radiofrequency signals to produce images from multiple planes. Ultrasonography uses reflected sound waves to display anatomy or flow as it happens.
Questions About This Page
How many codes are in the BY body system?
The BY body system contains 31 ICD-10-PCS codes in FY 2027, organized into 2 root operations. 29 of them are billable on inpatient claims.
What is a root operation?
The root operation is the third character of every ICD-10-PCS code and names the objective of the procedure. Drainage takes fluid out, Excision cuts out a portion of a body part, and Resection removes all of one. Picking the right root operation is the central skill of PCS coding, so each one above carries its official CMS definition.
Related References
Source: CMS FY 2027 ICD-10-PCS order file and code tables, effective October 1, 2026 through September 30, 2027.
