They may bump your meds. There are a lot of open questions about just how aggressively to manage hypertension in pregnancy--you don't want to be overly aggressive, because of the effects of the meds, and because there's a theory (which I may not explain too well) that the fetus is used to your baseline, a bit like a thermostat. So, if treatment is begun during pregnancy, they won't have as low a target as they might in a non-pregnant patient. But, they can and do adjust meds to keep you in a good range--they're just not as tight as they would be. Unfortunately, BP control does not seem to change the development of preeclampsia--we manage chronic HTN in pregnancy because it's better for you and baby if we do.
I began my second pregnancy controlled on meds and even though my baseline controlled was under 120/80, they maintained it that way (it rose slightly in that pregnancy but no superimposed PE).
Aliza - 01/05/2007 - Severe preeclampsia, emergency CS 37 weeks
Isaac - 09/26/2011 - controlled on 150mg Toprol, NO PE, 39 weeks!