Which code is NOT used from Chapter 15?

Chapter 15 of the ICD-10-CM code system specifically pertains to "Pregnancy, Childbirth, and the Puerperium." The codes in this chapter generally start with the letter "O," indicating that they are related to obstetrical conditions.

The code Z34, however, is found in Chapter 21, which covers "Factors Influencing Health Status and Contact with Health Services." This chapter's codes begin with "Z" and address situations that do not fit neatly into other chapters, such as routine healthcare encounters, including supervision of pregnancy without complications.

On the other hand, the codes O09, O80, and O10 are all part of Chapter 15 and address various aspects of pregnancy, such as complications and outcomes of childbirth. Therefore, the correct identification of Z34 as the code not found in Chapter 15 clearly follows from understanding the structure and categorization used in the ICD-10-CM coding system.