O88.21 ICD-10-CM Code: Thromboembolism in pregnancy

O88.21 is the ICD-10-CM diagnosis code for thromboembolism in pregnancy. O88.21 sits in the ICD-10-CM chapter for pregnancy, childbirth and the puerperium (o00-o9a), within the section covering complications predominantly related to the puerperium (o85-o92).

Header codes like O88.21 cannot be reported on claims directly, they organize child codes that share clinical context but the actual diagnosis must be coded to the highest level of specificity supported by the documentation. Coders should look at O88.21's child codes and select the one that matches the patient's documented presentation, since payers reject header codes submitted as the primary diagnosis. For risk adjustment workflows, header codes never contribute to a Medicare Advantage member's RAF score on their own; only billable child codes that happen to map to a payment HCC affect risk-adjusted plan payments.