O11Pre-existing hypertension with pre-eclampsia

O11 is the ICD-10-CM diagnosis code for pre-existing hypertension with pre-eclampsia. It belongs to block O10-O16 (edema, proteinuria and hypertensive disorders in pregnancy, childbirth and the puerperium) and chapter 15 (pregnancy, childbirth and the puerperium). It is a header code, so it can't be reported by itself; one of its 6 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: O11.1 (first trimester), O11.2 (second trimester), O11.3 (third trimester), O11.4 (complicating childbirth), O11.5 (complicating the puerperium) and O11.9 (unspecified trimester).

Use an additional code from O10 to identify the type of hypertension.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.