Pre-existing essential htn comp pregnancy, third trimester

This code signifies a patient with a pre-existing diagnosis of essential (primary) hypertension who is currently in the third trimester of pregnancy. The hypertension is considered to be complicating the pregnancy, requiring ongoing management and monitoring. This condition is distinct from gestational hypertension or pre-eclampsia, as the hypertension predates the pregnancy.

Apply this code when documentation clearly states a patient has a history of essential hypertension diagnosed prior to conception, and they are now in their third trimester of pregnancy. Supporting documentation would include a confirmed diagnosis of essential hypertension from before pregnancy, and current obstetric notes indicating the third trimester. This code should be used when the hypertension is impacting the pregnancy's course or management.

• Always sequence this code as a primary diagnosis when the hypertension is the main reason for the encounter or the primary condition being managed.
• Do not confuse with O13.- (Gestational hypertension) or O14.- (Pre-eclampsia), which develop during pregnancy.
• Ensure the medical record specifies "pre-existing" or "chronic" hypertension and the current trimester of pregnancy.