O99.331
Smoking (tobacco) complicating pregnancy, first trimester
Billable FY2026 2025-10-01 → 2026-09-30
Exclusions 6 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 9
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 2
Alongside this code 5 same parent — O99.33
O99.330 Smoking (tobacco) complicating pregnancy, unsp trimester O99.332 Smoking (tobacco) complicating pregnancy, second trimester O99.333 Smoking (tobacco) complicating pregnancy, third trimester O99.334 Smoking (tobacco) complicating childbirth O99.335 Smoking (tobacco) complicating the puerperium
Medications 3
9 Pregnancy Trimester, First drugs 34 Pregnancy Trimester, Third drugs 5 Pregnancy Trimester, Second drugs
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.