sVEGFR-1 (sFlt-1), a soluble form of VEGFR-1, can also trap VEGF, VEGF-B, and PlGF and therefore block their binding to membrane receptors [16,17], and its activity has been proven to be strongly correlated with unexplained infertility [18,19], recurrent miscarriage [20], and adverse pregnancy outcomes [21]. This evidence concerns the gene VEGFA and spontaneous abortion.