Hematological inflammatory biomarkers affecting the success rate of in vitro fertilization among cases of unexplained infertility Short running title: Hematological biomarkers and IVF outcome

Objective: This study aimed to evaluate the possible relation be- tween the outcome of in-vitro fertilization (IVF) in non-obese fe- males with unexplained infertility, and inflammatory indices ob- tained from complete blood count (CBC), including white blood cell and platelet counts (WCC and PC), neutrophil-to-lymphocyte-ratio (NLR) and platelet-to-lymphocyte-ratio (PLR).
Methodology: Forty lean cases (BMI <25 kg/m²) undergoing IVF for unexplained infertility were involved. This study evaluated the effects of CBC inflammatory markers, measured at the outset of ovarian stimulation protocol, on IVF outcomes.
Results: The mean values of CBC parameters were normal, ex- cept for 30% leukocytosis and 4% thrombocytosis. Despite simi-  lar embryological findings, the women who eventually got preg- nant had significantly lower WCC, neutrophil counts (NC), platelet counts (PC) and NLR (all p<0.001). On the other hand, thrombo- cytosis, lymphocyte counts and PLR were similar between wom-  en with positive and negative IVF outcomes. A significant correla- tion was found between platelet count and the number of oocytes and embryos, as well as the number of day-3 and grade I embryos.

The WCC, NC, PC as well as the NLR all had a significant diagnostic performance in predicting clinical pregnancy. The NLR showed the highest AUC (0.89), with a cutoff of ≤2.4, a sensitivity of 0.78 and a specificity of 0.9. On logistic regression analysis, the NC and PC were the most significant- ly affecting clinical pregnancy rate (p=0.011 and 0.049, odds ratio =0.25 and 0.95, respectively).
Conclusion: Poorer IVF clinical outcomes may be expected if unexplained infertility is associated with elevated WCC, NC, PC or NLR