Circulating levels of the angiogenic markers sFLT‐1 are increased in first versus second pregnancies. - Wolf,M.; Shah,A.; Lam,C.; Martinez,A.; Smirnakis,K.V.; Epstein,F.H.; Taylor,R.N.; Ecker,J.L.; Karumanchi,S.A.; Thadhani,R. (Am J Gyn Obstet, 2005)