**6. Conclusion**

We have described that recurrent implantation failure in IVF cycles depends on the interplay of many factors - female factors (different aspects of the uterine health), embryo factors (embryo quality and aneuploidy), possibly male factors (sperm DNA integrity), immunological factors, and probably many more. More investigations are needed before the clinicians can be clearly advised what diagnostic and treatment approaches must be implemented in the cases of RIF.
