Pre-existing hypertension with pre-eclampsia (O11)

The ICD-10 code O11 identifies cases of pre-existing hypertension with pre-eclampsia, a condition where chronic high blood pressure in pregnant women is complicated by pre-eclampsia. This code and its subcodes specify the timing of the condition throughout pregnancy, childbirth, and the postpartum period.

These codes are used specifically to document hypertension that existed before pregnancy but becomes complicated by pre-eclampsia, which is a serious disorder characterized by high blood pressure and signs of organ damage during pregnancy. The subcategories; from O11.1 to O11.5; detail whether the condition occurs during the first, second, or third trimester, complicates delivery, or the puerperium (postpartum period). The O11.9 code is used when the trimester is unspecified. This coding section helps healthcare professionals and coders accurately capture the complexity of managing high blood pressure that predated pregnancy and worsens with pre-eclampsia. Though no synonyms are listed for most codes, the O11.9 includes terms like “pre-eclampsia or eclampsia with pre-existing hypertension,” alerting coders that these codes specifically address cases where chronic hypertension is compounded by pregnancy-related hypertensive disorders.