Pre-existing hypertension w pre-eclampsia, third trimester

This code signifies a pregnancy complicated by the development of pre-eclampsia in a patient who had pre-existing hypertension prior to conception or before 20 weeks gestation. It specifically indicates that this condition is occurring during the third trimester of pregnancy.

Apply this code when documentation clearly states a diagnosis of pre-eclampsia superimposed on chronic hypertension, and the gestational age is beyond 28 weeks. Supporting documentation would include a history of hypertension, new onset of proteinuria and/or other signs of pre-eclampsia, and a confirmed third-trimester pregnancy.

• Always sequence this code as the principal diagnosis when it is the primary reason for the encounter.
• Do not confuse with gestational hypertension or pre-eclampsia without pre-existing hypertension.
• Ensure documentation specifies "pre-existing" or "chronic" hypertension to differentiate from gestational hypertension.