Prevalence of candidate single nucleotide polymorphisms on , , , and in patients with repeated implantation failure (RIF) and pregnancy loss (RPL).

Recurrent pregnancy loss (RPL; defined as the loss of three or more consecutive pregnancies) and recurrent implantation failure (RIF; when implantation is not achieved after at least three cycles of IVF) are two of the major challenges that reproductive medicine faces. Some polymorphisms have been identified as possible causes of an increased risk of these diseases. This paper studies the prevalence of the polymorphisms in , , -, - and in RIF and RPL patients that determines the risk for these pathologies. A total of 255 patients were selected (89 RPL patients, 77 RIF patients and 89 controls) and genotyped for ; ; ; ; ; . Statistically significant differences were found in the prevalence of the E4 isoform (R122-R158) of the gene in RPL patients ( < 0.05), and in RIF patients, the R72P polymorphism of the gene and the 1154-AG of the gene showed different distribution ( < 0.05). Regarding the and studied polymorphisms, PP of gene and GG of are more prevalent in RPL patients without reaching statistical significance. In conclusion, our results suggest patients carrying variants in and would be at risk of RIF, and those carrying variants in gene would suffer RPL.