Pre-existing secondary htn comp pregnancy, third trimester

This code signifies a patient in her third trimester of pregnancy who has pre-existing secondary hypertension, meaning her high blood pressure is caused by an underlying medical condition (e.g., renal disease, endocrine disorders) and was present before conception or diagnosed early in pregnancy. This condition complicates the current pregnancy, requiring careful management due to potential risks to both mother and fetus.

Apply this code when documentation clearly indicates a pregnant patient in her third trimester with a pre-existing diagnosis of secondary hypertension. The medical record must specify the underlying cause of the hypertension and confirm its presence prior to or early in the current pregnancy. This code is used when the hypertension is actively being managed or monitored as a complication of the pregnancy.

• Always code the underlying cause of the secondary hypertension first, if known and documented.
• Distinguish carefully from essential (primary) hypertension (O10.0-), gestational hypertension (O13.-), or pre-eclampsia (O14.-).
• Ensure the trimester is accurately documented to support the "third trimester" specificity.