Third degree perineal laceration during delivery, IIIb

This code signifies a severe obstetric laceration involving the perineum that extends through the perineal body, the external anal sphincter, and into the internal anal sphincter, but without disruption of the rectal mucosa. It specifically identifies a third-degree tear classified as IIIb, indicating the involvement of both external and internal anal sphincters. This injury occurs during the process of childbirth.

Use this code when documentation explicitly states a third-degree perineal laceration occurred during delivery, and further specifies the tear involved both the external and internal anal sphincters (IIIb). This code is appropriate for cases where the rectal mucosa remains intact. Supporting documentation includes operative reports, delivery notes, and physician's progress notes detailing the extent of the perineal trauma.

• Ensure the documentation clearly differentiates between IIIa (external anal sphincter only), IIIb (external and internal anal sphincters), and IIIc (external and internal anal sphincters with rectal mucosa involvement).
• Do not use this code if the rectal mucosa is also torn; a different code for a fourth-degree laceration would be more appropriate.
• Sequence this code as a secondary diagnosis following the code for the outcome of delivery (e.g., Z37.0 for single live birth).