Expression Levels of miR-99a and miR-143 in Women Diagnosed with Recurrent Pregnancy Loss

Background: Miscarriage is defined as the spontaneous loss of a pregnancy before fetal viability and includes all pregnancy losses occurring from conception until 24 weeks of gestation. Recurrent pregnancy loss (RPL) is traditionally defined as three or more consecutive miscarriages. Emerging evidence suggests that both miR-99a and miR-143 may serve as promising biomarkers for recurrent pregnancy loss. Methods: A total of 42 women of reproductive age (18-45 years) were enrolled in this study. The control group consisted of 13 women with no history of recurrent miscarriage, whereas the study group included 29 women diagnosed with spontaneous miscarriages/recurrent implantation failure. Results: Both miR-99a and miR-143 showed significantly lower relative expression in women with recurrent miscarriage/recurrent implantation failure compared with the control group. Conclusions: Despite the relatively small sample size, statistically significant differences in the expression of miR-99a and miR-143 were observed between the case and control groups, with lower relative expression of both miRNAs in the case group. These findings suggest that both microRNAs may be associated with molecular pathways involved in reproductive failure. Furthermore, investigating the expression patterns of miR-99a and miR-143 may contribute to a better understanding of the molecular mechanisms underlying recurrent miscarriage/recurrent implantation failure. Such insights may facilitate the development of genetic risk profiles for women with unexplained pregnancy loss and implantation failure, as well as support the identification of potential therapeutic targets. Further studies are required to determine their potential value as molecular markers and to clarify their functional relevance in reproductive failure.