Paternal factors in recurrent miscarriage : a role beyond conception

In normal pregnancy the fetus, although a semi-allograft, is tolerated by the maternal immune system. It has been suggested that an inadequate maternal allo-immune response to the paternal antigens of the fetus is responsible for a proportion of the unexplained recurrent miscarriage. In chapter 2 we provide an overview on the possible role of the HLA system in recurrent miscarriage. No consistent conclusions can be drawn since the observed odd ratios found were relatively small and the risk of bias in the selected studies was high. In chapter 3 we compared the genetic polymorphisms of HLA-G in women with recurrent miscarriage with women with uneventful pregnancy. The HLA-G UTR-4 haplotype was less frequently observed in women with recurrent miscarriage, suggesting an immunoregulatory role of this haplotype. The combined results from chapter 4, chapter 6 and chapter 7 suggest that in a portion of women with unexplained recurrent miscarriage antibody-mediated rejection of the fetal allograft may play a role. We showed in chapter 8 that human seminal plasma contains all kinds of immunoregulatory factors and has an immunomodulatory effect on T cells. In chapter 9 a matched case-control study practicing oral sex was negatively associated with the occurrence of recurrent miscarriage.