Endometrial Expression of Insulin Signaling Pathway Genes in Pregnancy Leading to Abortion under 20 Weeks in Infertile Women: A Case-Control Study

BACKGROUND: Impaired expression of genes which act on hormone signaling pathways is one of the factors affecting miscarriage. In this study, the expression levels of insulin receptor (INSR) and insulin receptor substrates-1 (IRS-1) genes in endometrial tissue of infertile women and fertile women with miscarriage in less than twenty weeks gestation for unknown reasons were evaluated. MATERIALS AND METHODS: In this case-control study, forty-two fertile women with children and 42 infertile women, who underwent in vitro fertilization (IVF), were selected. Both groups had abortions under twenty weeks gestation for unknown reasons. The endometrial tissue of all patients was prepared to evaluate the expression of INSR and IRS-1 genes by quantitative real-time polymerase chain reaction (PCR) method after RNA extraction. RESULTS: There was a statistically significant relationship between the expressions of INSR and IRS-1 genes in the endometrial tissue of the infertile women compared with the fertile women (P=0.002 and P=0.008, respectively). The expression level of genes was decreased in both groups by age and increasing body mass index (BMI). Comparison of genes expression levels in healthy and diabetic participants in each group showed a significant difference (P<0.0001), but no meaningful difference was indicated between diabetic infertile and fertile groups in terms of gene expression. INSR gene expression levels showed an increase in the fertile group in the second 10 weeks and a decrease in IRS-1 gene expression. But in the infertile group, both genes showed a slight increase in expression. CONCLUSION: It seems a decreased expression of insulin signaling pathway genes in the endometrial tissue of infertile women can be one of reasons for unspecified abortion. These genes may be strong molecular markers for infertility.