I don't usually code OB (so take my opinion with a grain of salt) however I'd just like to add an article I found. This is taken from the ICD-10-CM and ICD-10-PCS Coding Handbook. Based on this article, if the patient has a history of gestational diabetes in a previous pregnancy you are to use Z86.32.
Diabetes mellitus is a significant complicating factor in pregnancy. Pregnant women who are diabetic should first be assigned a code from category O24, Diabetes mellitus in pregnancy, childbirth, and the puerperium, followed by the appropriate diabetes code(s) (E08-E13) from chapter 4 of ICD-10-CM.
Similar to the classification of hypertension, category O24 distinguishes between pre-existing diabetes mellitus (including type 1, type 2, other, or unspecified), gestational diabetes, and unspecified diabetes as follows:
| O24.011-O24.03 | Pre-existing type 1 diabetes mellitus |
| O24.111-O24.13 | Pre-existing type 2 diabetes mellitus |
| O24.311-O24.319 | Unspecified pre-existing diabetes mellitus |
| O24.410-O24.439 | Gestational diabetes mellitus |
| O24.811-O24.83 | Other pre-existing diabetes mellitus |
| O24.911-O24.93 | Unspecified diabetes mellitus |
Gestational (pregnancy-induced) diabetes can occur during the second and third trimesters of pregnancy in women who were not diabetic prior to pregnancy. Gestational diabetes can cause complications in the pregnancy similar to those of pre-existing diabetes mellitus. Women with gestational diabetes are at increased risk to develop diabetes mellitus following delivery. Codes for gestational diabetes are in subcategory O24.4, Gestational diabetes mellitus. No other code from category O24, Diabetes mellitus in pregnancy, childbirth, and the puerperium, should be used with a code from O24.4. The codes under subcategory O24.4 classify gestational diabetes as diet controlled, insulin controlled, or controlled by oral hypoglycemic drugs. If a patient with gestational diabetes is treated with both diet and insulin, only the code for insulin controlled is required. If a patient with gestational diabetes is treated with both diet and oral hypoglycemic drugs, only the code for "controlled by oral hypoglycemic drugs" is required.
Code Z79.4, Long-term (current) use of insulin, should be assigned as an additional code if the pre-existing or unspecified diabetes mellitus is being treated with insulin. Code Z79.4 should not be assigned if insulin is used temporarily to bring the blood sugar under control in a patient with pre-existing type 2 diabetes. Code Z79.84, Long-term (current) use of oral hypoglycemic drugs, should be assigned if the pre-existing or unspecified diabetes mellitus is being treated with oral hypoglycemic drugs. However, codes Z79.4, Long-term (current) use of insulin; Z79.84, Long-term (current) use of oral hypoglycemic drugs; and Z79.85, Long-term (current) use of injectable non-insulin antidiabetic drugs, should not be assigned with codes from subcategory O24.4, Gestational diabetes. If a patient with gestational diabetes is medication controlled, the appropriate medication-controlled code (O24.414, O24.415, O24.424, O24.425, O24.434, or O24.435) should be assigned instead of Z79.4, Z79.84, or Z79.85.
A pregnant patient may have an abnormal glucose tolerance and not be diagnosed with gestational diabetes. In such cases, a code from subcategory O99.81, Abnormal glucose complicating pregnancy, childbirth, and the puerperium, should be assigned instead.
Code Z86.32, Personal history of gestational diabetes, is assigned to indicate that a patient has a history of gestational diabetes in a previous pregnancy.
Examples include the following:
O24.113 + E11.620 + Z79.4 + Z3A.29
Pre-existing type 2 diabetes mellitus, with diabetic dermatitis, on insulin, intrauterine pregnancy, 29 weeks' gestation
O24.012 + E10.11 + Z3A.26
Pre-existing type 1 diabetes mellitus, ketoacidosis, and in coma; intrauterine pregnancy, 26 weeks' gestation
O24.414 + Z3A.30
30 weeks pregnant female seen in physician's office with gestational diabetes; blood sugar testing reveals her diabetes is under good control with both diet and insulin
Designated conditions, such as edema, proteinuria, and hypertensive disorders in pregnancy, childbirth, and the puerperium are classified to categories O10 through O16.
Other maternal disorders, such as hemorrhage, hyperemesis gravidarum, venous complications, genitourinary infections, diabetes mellitus, malnutrition, and liver disorders, are classified to categories O20 through O29 when they complicate the obstetric experience.