Pre-eclampsia @ 34 weeks.....WHY?

I haven't posted in a few days so I thought I would give everyone an update and I had a few questions as well.  I decided to take a trip to the hospital on Monday evening b/c I was having contractions that were 3-5 minutes apart and hurting pretty badly.  They put me on the monitor for about two hours and ran a few tests and everything came back negative!  So that was great. I was 2 cm dilated and 80% effaced.  They only thing that was a bit concerning was my bp which was 148/83 and for me thats high.  But they sent me home anyways and told me to relax and take it easy.  I had a doctor's appt anyways the following day, so I was like ok.
When I got to my doctors office she was running out to go deliver a baby and didn't end up coming back so I thought well while I am here I will get my bp checked.  It was 155/104.  So they sent me right on over to L&D to be admitted since my doctor was already there.  I ended up having to do the 24 hour urine test and they put me on the monitors and gave me fluids and told me that I was going to be there for 24 hours.  I stayed and my bp still was high. The only time it was low was during the night and then it went back up the following morning.  They checked my urine and it had high amounts of protein and so they decided to keep me another night to monitor me and the baby more doing stress tests every so often.  So my doctor told me I had pre-eclampsia and that she wanted me on strict bedrest til 36 weeks.  She was talking about inducing me b/c she was a bit concerned that my bp didn't go down even while I was in the bed.  So told me I would be a walking heart attack waiting to happen if I was up and moving since my number were high when I was just relaxing.
My question is...What causes pre-eclampsia in women?  I mean I had it with my DD and so I knew there was a possibility it would happen again, but not this bad.  Last time I didn't get it until 38 weeks and I was induced right away and they ended up giving me Magnesium after I was induced, but why did it show up @ 34 weeks this time around?

[Cheyenne_08]

My doctor said that there is NO WAY to determine why it happens and that it just does!!! My risk of pre-eclampsia was so high that my high risk doctor said that his goal for me was 27 weeks because he guarenteed I would not make it to full term because my blood pressure was dangerously high starting at 19 weeks!!!! I ended up going into labour at 29 weeks, and then again 4 days later! But we did make it to 31 weeks and Ashtyn was healthy! Anyway, to answer your question, it can show up at any time and there is really no certain thing that makes it happen at a certain time.

[tiredbuthappy]

my dr also said they have no clue what causes it and there's nothing you can do to prevent it. i had to have a c-sec at 36 due to it. my dr didn't want to try inducing because it was so early and i was no where near ready for labor. he thought it we induced i would end up needing a c-sec anyways. thank god too because by the time i got to the hospital for the c-sec i was so sick i could barely stay awake. take it easy! i assume they told you symptoms to watch for.

[bjbbeauchamp]

thanks to both.  Yeah, it's just crazy how i have never had high bp in my life until when I get preggo.  It makes me feel so icky.  I felt so wonderful except for the painful contractions I started having @ 24 weeks.  All I do is lay around and nothing seems to help keep it down.  Everyone has been so kind in helping me out with my little one and the house, but I hate not being able to do anything myself.  But I know it's best for me and the baby.  I read that the only way to get rid of pre-eclampsia is to deliver.  I kind of figured that, but really didn't know how serious it was until I read into it last night.  With my first my bp didn't really get that bad until 38 weeks and that's when I was induced, so no real harm there, but I am scared to wait especially since we have been monitoring it at home and it is still high.  I have a doctor's appt on Monday and I am going to really stress my concern about my health.  At the doctor's appt I will only have 1 week and a day left, so that's not too long of me having to just take it easy. Please say a prayer for us that we will be able to make it safely to 36 weeks.