I am currently 34.6 weeks with my second pregnancy after getting hellp with my first at 32 weeks.
From what I found out the odds are that the chances you will get hellp again are from 5-25% but the odds of getting pe are up to 40%. i have read that some women have been given a 60% chance of getting pe again. it really comes down to when you get it in your first pregnancy. the earlier the worse the prognosis for the second pregnancy BUT from what I found most people go further in their pregnancies and have it less severe if they get it at all.
for a second pregnancy the medical people will take it slightly more seriously and you will get more follow up if this is what you want. most people get more scans and get started on aspirin. This is supposed to help with the clotting that can happen in the placenta and the potential cause ( no one seems to have a good idea why it happens). i went on aspirin from 13-23 weeks and then went off it. the research is ok but there is nothing statistically significant about the research that being on aspirin will have a dramatic impact on reducing pe. but then it is a personal choice.
lifestyle factors also have an impact i think. awareness of diet rest, exercise and stress i think have a dramatic effect, so we kept this in mind when thinking of having another baby. there is some research coming out about coenzyme q10 has having an impact on the reduction of pe as well which is what i am taking.
good luck. it is pretty full on embarking on the decision to have another baby, but I have to say that this pregnancy has been vastly different from my last!!!