Hi Dan,
I had just started a thread on high blood pressure in the general pregnancy discussion when I came across your one. DOH! Anyway, this is what I wrote (am lazy and can't be bothered typing it again):

At my first appointment at the hospital, my blood pressure was a little high. I have had a history of it going up and down (usually with my weight) and, because of that, I am ineligable for shared care. I have been put into the "High Risk category so I have to go through the Doctors at the hospital until we get it under control.
I have been told that there is medication that I can take during pregnancy for the high blood pressure and it is completely safe. I am hoping it doesn't go that far but at least I know it can be controlled if needs be.
The last 3 months, I have been doing little or no exercise and haven't been eating extremely well because of morning sickness (all day sickness, night time sickness etc.). When I get home from work, I am so tired that all I want to do is flake on the couch. It all sounds like excuses (and I am really good at those) but I honestly don't have the energy.
Anyway, today is the day that I am going to force myself to go on a walk. I am not going to overdo it but at least go around the block to start off with. I have been told not to do anything more strenuous than walking for the moment because I haven't done anything for such a long time. I just hope I don't need to hurl in someone's front yard! Urrgh!

So, I am probably going to be similar to you. My BP has been up and down ever since I was about 18 and it will probably be the same afterwards. My Mum has been on medication for it for years and she also has kidney problems and type 2 diabetes. So, of course, the drs will be monitoring me closely for pre-eclampsia and gestational diabetes. My Mum didn't get either of those when she was pregnant - just high blood pressure. However, she was a good 7 years younger than me when she had her first. In fact, my my age, she was preggers with her 5th child! I don't know if age has anything to do with it. I am more thinking along the lines of high BP progressing to something more serious as time goes on iykwim?
I know that if I lose weight, my BP goes down. I lost 17kgs on WW last year and I felt great, BP was down and I was exercising every day. But it was DAMN hard work! I got my new job and it kinda took the focus away from counting points etc. It's all excuses but I fell off the wagon and put all the weight back on. Now I am pregnant and so sick with m/s that exercise has fallen by the wayside. I feel so fat - not pregnant fat as it is my tummy that is expanding, not my abdomen. So, I have to do something about it. Hopefully my BP will sort itself out without medication but, if needs be, I will take it for the health of my baby.