First trimester neutrophil-to-lymphocyte ratio (NLR) and pregnancy outcomes in medically assisted reproduction (MAR): a case control study.

As success rates after medically assisted reproduction (MAR) technologies have remained constantly limited during the last years, there has been a systematic effort to predict clinical outcomes. There is currently weak evidence to name the neutrophil-to-lymphocyte ratio (NLR), as an accurate predictor in MAR. Through a case control study, and by setting strict eligibility criteria, we enrolled 66 women (35 with negative outcome and 31 cycles with live birth), in terms of NLR at the time of oocyte retrieval. Clinical and IVF cycle characteristics were comparable in a normalized population. There was a positive correlation between NLR and the age of the woman (r = 0.310, p=.011 and rs =0.363, p=.033). Higher odds ratios (ORs) of MAR positive outcome were detected only at higher NLR values, when NLR was divided into quartiles, but only in the 4th quartile [OR =4.33 (95%CI: 1.02-10.79)]. ROC curve resulted on an AUC equal to 0.660 (95%CI: 0.529-0.791) and p value .025. The estimated specificity, sensitivity and cutoff point were 0.57, 0.548, and 1.98, respectively, while PPV and NPV values were 70.6% and 59.3%, respectively. In conclusion, NLR was positively correlated with maternal age; in our study cohort, MAR failure was associated with lower NLR values.