Determinants of Repeated Spontaneous Miscarriages and Unexplained Fetal Deaths

Overview

The DEFI-1 study recruited 625 women witnesses and 299 of their spouses. With regard to case couples, 271 cases were recruited from the spontaneous repeated miscarriages (SRM) subgroup (≥3 spontaneous miscarriage (SM) from trimester 1 of pregnancy) and 93 from the unexplained fetal death in utero (FDIU) subgroup from trimesters 2 and 3 of pregnancy. The main objective of the DEFI 2 study is to increase the number of case-pairs in these 2 particular subgroups to replicate the results of the genetic determinants highlighted from cases and controls with extreme phenotypes and obtain a sufficient number of women with FDIUs to identify specific determinants.

The spontaneous repeated miscarriages (SRM) affect one to two fertile couples on 100, a fetal death in utero (FDIU) complicates the evolution of a pregnancy on 200. The SRM remain unexplained in 50% of the cases although a beam indirect arguments sometimes encourage to evoke a prothrombotic process and / or endothelial dysfunction, immunological disorders, an alteration of the ovarian reserve, and possibly the impact of genetic determinants. Regarding SRM, in the absence of a fetal, funicular cause or obvious preeclampsia, very diverse mechanisms are evoked depending on the placental histology (vasculoplacental, inflammatory, intervillitis, immunological, etc.). Thus, while these mechanisms remain for some to be demonstrated and are probably not unequivocal, clinicians are faced with a pressing request for therapeutic intervention on the part of patients. This is why, after having studied in DEFI-1 the 2 main constitutional thrombophilia in the 2 members of the couple, the procoagulant circulating microparticles and the generation of thrombin in the mother on the one hand, the modalities of inactivation of an X in the mother, on the other hand, a further investigation in subgroups of particular cases would be appropriate.