Vagnini LD, et al. - Researchers performed this cohort study investigating an association between polymorphisms related to the implantation process that together could help in the prediction of recurrent implantation failure (RIF). They analyzed 44 women presenting RIF (RIF group), and two control groups, one with 63 women who became pregnant after the first IVF/intracytoplasmic sperm injection attempt (control group I) and other with 65 fertile women who had at least two children without any treatment and no history of miscarriage (control group II). Using real-time polymerase chain reaction, they performed genotyping in the intron region of TP63, VEGFA, MMP2, ESR1, and ESR2 genes and in the 3′ untranslated region of the LIF gene on genomic DNA. The RIF group more frequently had ESR1/AA (rs12199722) and LIF/GT (rs929271) genotypes, suggesting the potential utility of the association between ESR1 and LIF polymorphisms in the prediction of RIF.