Fibrin D-dimer levels in preeclamptic pregnancies with birth of small-for-gestational-age neonates

Objectives: To investigate whether levels of fibrin D-dimers (D-dimer) are increased in the hypercoagulable state of preeclampsia with birth of small-for-gestational-age (SGA) neonates; if so, to relate these changes to alterations in the coagulation and/or fibrinolysis pathways. Subjects and Methods: A retrospective investigation of D-dimers levels, determined in gestational weeks 30-35, was made in 25 normal pregnant women and 32 preeclamptic patients who gave birth to SGA or to appropriate-for-gestational-age (AGA) neonates. Levels of fibrinogen, thrombin-antithrombin complex, soluble fibrin, and plasminogen activator inhibitors 1 and 2 (PAI-2) were also analyzed. Results: In the SGA group compared with the AGA, the D-dimer level was lower (P < 0.01) but still higher than in women with normal pregnancies (P < 0.01). Levels of other variables were not significantly changed (P > 0.05), except for a further decreased PAI-2 level (P < 0.01). The D-dimer concentrations were correlated to the severity of SGA (r(s) = 0.65, P < 0.01) and to the incidence of placental infarction. Comment: Our hypothesis was contradicted by the relative reduction in the D-dimer levels in the SGA group. This decline may be a consequence of more severely depressed fibrinolysis, which, in turn, may be due to inadequate placental function. It remains to be elucidated whether the reduction in the D-dimer levels in the SGA group depended on an acquired deficiency of an urokinase-type plasminogen activator which may contribute to inhibition of fibrinolysis as well as to impairment of trophoblastic invasion.