DISCUSSION
RPL
RECURRENT MISCARRIAGE, ADVERSE EFFECTS, CONTRACTIONS
Recurrent miscarriage (RPL) in up to half of cases may have no known cause [Other than examining the embryo itself as a potential contributing factor to unexplained RPL, the capacity of the endometrium to distinguish between low-quality and high-quality embryos has received attention recently [Therefore, in this study, two pharmacological agents were selected, one to enhance blood flow and the other to increase uterine blood flow and potentially reduce the risk of myometrial contractions, and compared their efficacy and safety in enhancing endometrial blood flow and thickness. The results of this study demonstrated that both agents were equally safe, as there were no significant differences in the rate of adverse effects. Additionally, both agents resulted in similar improvements in the pulsatility index. However, when comparing the resistive index and endometrial thickness, Sildenafil was more effective than Nifedipine. Sildenafil led to a greater reduction in the resistive index and a greater increase in endometrial thickness. These findings align with the results of Saleh This study has several limitations, including small sample size and short duration, which may limit the statistical power and generalizability of our findings. Being a single-center study introduces potential bias and restricts the external validity. The significant variation in body mass index among participants could confound the results. Future studies should include larger sample sizes, longer follow-up periods, and multicenter designs to overcome these limitations and validate our findings. Controlling for confounding variables and considering diverse populations would improve reliability and generalizability. Further research should explore the long-term effects of Nifedipine and Sildenafil on pregnancy outcomes, optimize dosing regimens, and investigate combination therapies to enhance efficacy.