Welcome to the forums. I'm glad you've found us.
Since you've had it in two pregnancies, it is more likely that you will have it in any future pregnancy, especially pregnancies with the same partner. It's not something over which you have any control, so please don't feel guilty for not being able to deliberately control it! These syndromes appear to be the result of the combination of your genes and the genes of your partner interacting. Our immune systems are reacting to the proteins from our partners that make up the placenta. This is very common in human pregnancy and is likely to be the explanation for our high rate of miscarriages, preterm labor, and preeclampsia. Humans have very complicated placental beds that predispose us to difficult pregnancies.
Some women also have underlying conditions - like APS, or chronic hypertension - that make any pregnancy more likely to become medically complicated.
Are you being seen by a maternal-fetal medicine specialist for this pregnancy? With a history of two cases of severe preterm onset, you are likely to be a candidate for management by a MFM. Here's a link to help you find one in your area: http://www.smfm.org
(search by state for a specialist in your area.)