ICD-10 coding for pregnancy complications

As physicians and coders transition to the International Classification of Diseases-10th Revision-Clinical Management (ICD-10-CM), several coding and documentation issues will need to be addressed related to complications of pregnancy.

Codes for reporting complications of pregnancy, childbirth, and the puerperium are in chapter 15 of ICD-10-CM and begin with the letter O. Including the trimester in which the condition occurs, and seventh digits to identify the fetus affected, when necessary, are the main structural changes for classifying complication of pregnancy codes. The episode of care designations used in ICD-9-CM are no longer an axis of classification in ICD-10-CM.

For complications of pregnancy, the trimester during which the complication occurs is part of the code selection in ICD-10-CM and the trimester should be documented. The number of weeks the patient is pregnant will determine the code selection. In ICD-10-CM, there is no longer the fifth digit classification for episode of care that is used in ICD-9-CM. The trimester is included as part of the complete code description.

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Chapter level instructions also note that an additional code from category Z3A Weeks of gestation also be assigned to identify the specific week of the pregnancy, and is used only on the maternal record.

For some complication of pregnancy codes, seventh character extensions are required to be added in order to complete a valid, reportable code. These seventh character extensions identify the fetus affected.

The seventh character ‘0’ is for single gestations and multiple gestations where the fetus affected is unspecified. The seventh characters 1 to 9 are for cases of multiple gestations to identify the fetus for which the code applies. Further coding instructions may also require that a code from category O30 Multiple gestation be assigned when reporting a code with a seventh character.

After presenting the basic coding structure changes for reporting pregnancy complication codes in ICD-10-CM versus ICD-9-CM, this article now examines the differences in the two classification systems for reporting the specific condition of diabetes mellitus in pregnancy, which has been greatly expanded in ICD-10-CM.

In ICD-9-CM, diabetes mellitus (DM) complicating pregnancy, childbirth, or the puerperium is reported with 648.0x, and gestational diabetes is reported with 648.8x Abnormal glucose tolerance. Each requires a fifth digit of 0-4 for the episode of care. In ICD-10-CM, DM in pregnancy, childbirth, and the puerperium, category O24, has been divided into 6 subcategories, each with further subclassified codes for valid reporting. The six subcategories specify pre-existing DM, type 1; pre-existing DM, type 2; unspecified pre-existing DM; Gestational DM; Other pre-existing DM; and unspecified DM. Each of these subcategories provides codes specifying the trimester of pregnancy, in childbirth, and in the puerperium. Both systems require the use of additional codes to further specify the manifestations.

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Unspecified pre-existing DM (O24.3-) is reported when the patient had diabetes before becoming pregnant; however, the type is not specified. Any additional diabetes codes reported from the endocrine chapter used to further identify the particular manifestations must be selected from category E11 for type 2 as the default. Unspecified DM (O24.9-) is reported when it is not known whether the diabetes arose during pregnancy or is pre-existing.

Other pre-existing DM (O24.8-) is used when the patient had either DM due to another underlying condition, such as Cushing’s syndrome; drug or chemical induced DM; DM due to genetic disorders/defects; or other secondary (post-procedural) DM prior to pregnancy. Additional codes reported with O24.8- for the particular diabetic manifestations must be selected from the category in the endocrine chapter that reflects the appropriate type of other (pre-existing) diabetes. These will be from category E08, E09 or E13. In both classification systems, a code for long-term (current) use of insulin is also provided.

Gestational diabetes codes in ICD-10-CM have a slightly different structure than that of the pre-existing or unspecified DM in pregnancy codes. Gestational diabetes is subdivided into codes that specify whether it is diet controlled, insulin controlled, or unspecified control in pregnancy.