During pregnancy, it's not "postpartum" — it's just preeclampsia. It can go into full blown eclampsia. "Postpartum preeclampsia" happens post birth. It can be the more dangerous because it may not arise until after the mother has gone home.

I had preeclampsia too. I was in hospital for three and half weeks before my son was delivered almost six weeks early, by emergency c-section when I entered in full-blown eclampsia. My BP fluctuated during delivery, but returned to normal in post-op.