I have been fortunate and not experienced any miscarriages myself but one of the diseases I was tested for after having severe preeclampsia was Antiphospholipid syndrome. To be diagnosed with APS, along with the actual blood test results you had to have a certain number of unexplained miscarriages or an early birth due to PE. Maybe you can talk to your OB or MFM/Perinatologist about it and see if that was one of the tests they were running.
Mommy of Three Boys- Davis 10/4/2007(No PE, overbaked at 40wks, 2 days),
Cooper 5/20/2010-5/21/2010 (born too early at 24wks, 2 days due to severe PE) and
Blaine 10/11/11 (35wks, 6 days, mild but quick moving PE)
Wife to Matthew since 6/11/2005