Generally, if all you can bill is 99211 you won't be reimbursed for this during the PP period as the work of the visit would not be considered significant. If she is seen periodically just for the hypertension by a provider (not just the nurse), I would consider billing those visits. You will most likely get a denial if your payer wants global coding, but at least you have the claim in the system to challenge at the end of the pregnancy so the extra care does not get denied due to timely filing issues. Alternatively, if she is seen say weekly for BP checks you might have a case to add a modifier -22 after delivery for significant additional work.