Did you take Dex at all during your pregnancy???  I had high BP for a few months after my last 2 pregnancies (1 at 40 and 1 at 41....silly me).  I didn't take dex in the last pregnancy since I thought it was giving me the high BP, but I guess not.  I used to have a normal low BP of 90/50...not anymore.  It has since gone down to about 105/70...5 months after the last birth.