Gestational htn w/o significant proteinuria, third trimester

This code represents new-onset hypertension (blood pressure $\geq$ 140/90 mmHg) occurring after 20 weeks of gestation, specifically during the third trimester, without any signs of proteinuria or other systemic features of pre-eclampsia. It signifies a transient hypertensive state induced by pregnancy that typically resolves postpartum.

Use this code for pregnant patients presenting with elevated blood pressure readings in the third trimester, confirmed by at least two measurements taken four hours apart, in the absence of pre-existing hypertension or proteinuria. Documentation should clearly state "gestational hypertension" and specify "third trimester" with no mention of proteinuria.

• Ensure documentation explicitly states "without significant proteinuria" or "no proteinuria" to differentiate from pre-eclampsia.
• Do not use this code if hypertension was present before pregnancy or diagnosed before 20 weeks gestation; consider codes from category O10.
• Sequence this code as the primary diagnosis when it is the reason for the encounter, or as a secondary diagnosis when managed concurrently with other pregnancy-related conditions.