O24.313
Unspecified pre-existing diabetes mellitus in pregnancy, third trimester
This code does not map to a risk-adjusting HCC in the loaded models.
Coding notes
Excludes 1 never coded together · Excludes 2 may co-exist
supervision of normal pregnancy (Z34.-)
mental and behavioral disorders associated with the puerperium (F53.-) obstetrical tetanus (A34) postpartum necrosis of pituitary gland (E23.0) puerperal osteomalacia (M83.0)
code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.
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
Official Guidelines for O24.313
FY 2026 ›Subsections
- I.C.15.aGeneral Rules for Obstetric Cases
- I.C.15.bSelection of OB Principal or First-listed Diagnosis
- I.C.15.cPre-existing conditions versus conditions due to the pregnancy
- I.C.15.dPre-existing hypertension in pregnancy
- I.C.15.eFetal Conditions Affecting the Management of the Mother
- I.C.15.fHIV Infection in Pregnancy, Childbirth and the Puerperium
- I.C.15.gDiabetes mellitus in pregnancy
- I.C.15.hLong term use of insulin and oral hypoglycemics
- I.C.15.iGestational (pregnancy induced) diabetes
- I.C.15.jSepsis and septic shock complicating abortion, pregnancy, childbirth and the puerperium
- I.C.15.kPuerperal sepsis
- I.C.15.lAlcohol, tobacco and drug use during pregnancy, childbirth and the puerperium
- I.C.15.mPoisoning, toxic effects, adverse effects and underdosing in a pregnant patient
- I.C.15.nNormal Delivery, Code O80
- I.C.15.oThe Peripartum and Postpartum Periods
- I.C.15.pCode O94, Sequelae of complication of pregnancy, childbirth, and the puerperium
- I.C.15.qTermination of Pregnancy and Spontaneous abortions
- I.C.15.rAbuse in a pregnant patient
- I.C.15.sCOVID-19 infection in pregnancy, childbirth, and the puerperium
Sections that reference O24.313
- I.C.15.gDiabetes mellitus in pregnancy
… Pregnant patients who are diabetic should be assigned a code from category O24, Diabetes mellitus in pregnancy, childbirth, and the puerperium, first, followed by the appropriate diabetes code(s) (E08-E13) …
- I.C.15.iGestational (pregnancy induced) diabetes
… Codes for gestational diabetes are in subcategory O24.4, Gestational diabetes mellitus. …
- I.C.15.a.1)Codes from chapter 15 and sequencing priority
Obstetric cases require codes from chapter 15, codes in the range O00- O9A, Pregnancy, Childbirth, and the Puerperium. …
Sections whose FY 2026 text names O24.313, its O24 category, or a range containing it — the chapter guidance above is the authoritative source.