O99.412
Diseases of the circulatory system complicating pregnancy, second trimester
Billable FY2026 2025-10-01 → 2026-09-30
Exclusions 11 never code together
O99code
Excludes2
- when the reason for maternal care is that the condition is known or suspected to have affected the fetus (O35-O36)O35-O36
O00-O9Achapter
Excludes1 — never code together. The excluded condition and this one are mutually exclusive.
Excludes2 — not included here, but the patient may have both. Code both when documented.
Instructional notes 10
O99code
Includes
- conditions which complicate the pregnant state, are aggravated by the pregnancy or are a main reason for obstetric care
Use additional code
- code to identify specific condition
O00-O9Achapter
Notes
- CODES FROM THIS CHAPTER ARE FOR USE ONLY ON MATERNAL RECORDS, NEVER ON NEWBORN RECORDS
- Codes from this chapter are for use for conditions related to or aggravated by the pregnancy, childbirth, or by the puerperium (maternal causes or obstetric causes)
- Trimesters are counted from the first day of the last menstrual period. They are defined as follows:
- 1st trimester- less than 14 weeks 0 days
- 2nd trimester- 14 weeks 0 days to less than 28 weeks 0 days
- 3rd trimester- 28 weeks 0 days until delivery
Use additional code
- code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.Z3A
Index entries leading here 1
Alongside this code 3 same parent — O99.41
Medications 2
MED-RT files conditions by MeSH, which carves the world differently from ICD-10. These are name matches on this code's description, offered as candidates — not as an assertion that they are this code.
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.