Recurrent implantation failure: which patients benefit from endometrial scratching prior to IVF?

Purpose: Endometrial scratching (ES) using a biopsy catheter prior to the IVF cycle in the repeated implantation failure (RIF) population has been suggested, but no convincing evidence of its benefit has been presented until now. Methods: A retrospective mono-center study among 300 consecutive IVF-RIF cycles following evaluation of the ovarian reserve, hysterosalpingography or hysteroscopy, pelvic ultrasound, thrombophilia evaluation, karyotyping and assessment of male sperm parametrs. The findings within normal limits. All the patients offered ES, 78 consented and underwent ES prior to their next IVF cycle. Results: A comparison of treatment outcomes between the post-ES cycles (n = 78) and the non-ES cycles (222) demonstrated the following: 34 (43.5%) versus 14 (6.3%) conceptions, respectively (p = 0.001) and 30 (38.4%) versus 2 (0.9%) clinical pregnancies, respectively (p < 0.001%), emphasizing an extremely high biochemical pregnancy rate among the non-ES cycles. Implantation rate was 19.7% versus 0.4%, respectively (p < 0.001) and live birth rate was 33.33% (26 newborns) versus 0.45% (1 newborn), respectively (p < 0.001). Since there were more embryos available for transfer and more top-quality embryos in the post-ES–IVF conception cycles, the role of ES became questionable. A multivariate analysis that included ES and the percentage of top-quality embryos demonstrated that ES was an independent factor highly correlated with conception in this particular RIF population. Conclusions: ES proved to be an efficient tool in a particular subgroup of RIF patients with fertility investigation results within normal limits, an optimal ovarian response to gonadotropins, and a high percentage of top-quality embryos. Nevertheless, the results should not be overestimated, since the study has limitations related to its retrospective model.